Ballparks come in all different shapes and sizes. Basketball, football, and hockey all play on the same dimensions. But baseball is different. There are some beautiful parks, historic parks, and parks that feel like a cave (*cough* the Trop *cough*). No two ballparks are the same in baseball and that's part of the beauty of the sport. Certain ballparks are better for offense and others are great for pitchers. Let this piece help you in identifying the science behind these parks as well as why DFS players will target the chalk players when playing in Coors Field or Miller Park!

Ballparks on the Rise

To kick off the 2019 version of the Ballpark Factors article we’ll keep it simple and briefly touch on the best offensive parks in baseball from 2017 and 2018. In 2017 the ballparks with the highest home run rate were:

  1. Citizens Bank Park (Philadelphia Phillies)
  2. Yankee Stadium (New York Yankees)
  3. Orioles Park at Camden Yards (Baltimore Orioles)
  4. Chase Field (Arizona Diamondbacks)
  5. Coors Field (Colorado Rockies)
  6. Target Field (Minnesota Twins)
  7. Guaranteed Rate Field (Chicago White Sox)
  8. Comerica Park (Detroit Tigers)
  9. Globe Life Park in Arlington (Texas Rangers)
  10. Great American Ball Park (Cincinnati Reds)

No surprise with a lot of those parks. Coors Field will always be near the top for home runs and offense in general. Yankee Stadium with its short porch in right field along with the powerful bats in their lineup will provide for a lot of offense as well. Target Field is well known for catering to offense and power hitters, and once in warms up in Cincinnati, Great American Small Park is a hitter’s dream in the summer. 2018 saw some new faces crack the top ten as shown below:

  1. Great American Ball Park (2017 rank: 10)
  2. Coors Field (2017 rank: 5)
  3. Globe Life Park in Arlington (2017 rank: 9)
  4. Citizens Bank Park (2017 rank: 1)
  5. Nationals Park (2017 rank: 13)
  6. Yankee Stadium (2017 rank: 2)
  7. Angel Stadium of Anaheim (2017 rank: 18)
  8. Rogers Centre (2017 rank: 21)
  9. Oriole Park at Camden Yards (2017 rank: 3)
  10. Miller Park (2017 rank: 12)

Rogers Centre made a massive jump from 2017-to-2018 and the annoying thing is that there really isn’t any explanation for it. The dimensions for the park haven’t changed and there wasn’t a significant amount of games played with the roof open. Rogers Centre has just always fluctuated from year-to-year with little explanation despite its reputation as a hitter’s ballpark according to Baseball Prospectus’ Toronto Column:

 

Runs Scored

Home Runs

Hits

2015

24th

15th

26th

2016

6th

17th

8th

2017

21st

21st

17th

In 2015 and '16 the Blue Jays made the ALCS each season and in 2016 they had six players hit at least 20 home runs so there was certainly plenty of power. But yet, Rogers Centre has fluctuated either way. In terms of home runs, Rogers Centre was declining from 2015-2017 and yet in 2018 it cracked the top eight. If being objective, I’d be willing to say it had a little something to do with the division they play in. The Yankees and Red Sox represented roughly 20% of the Blue Jays opponents at home last year and those two teams have exceptional offenses. Since the Blue Jays didn’t have a single player hit 30 home runs last year, I’m willing to come to terms with the fact that opposing offenses benefitted more in this ballpark than the home team did.

Another park that made a significant jump would be Angels Stadium of Anaheim that jumped from 18th to 7th in home run rate. Fortunately for the readers (and myself) there’s an explanation for this. Kudos to Mike Petriello of MLB.com who Predicted last February that there would be an increase in home runs at The Big A. Last offseason the Angels announced they would be lowering their right field wall by about 10-feet, cutting it down from 18-feet tall, to just eight-feet tall at the start of the 2018 season. Statcast predicted an 8.5% increase (about 16-18 more home runs) for this park. Considering there were 81 home games for the Angels, that translates to almost an extra home run every five games. Now the Angels are in a bit of a leasing issue with the city of Anaheim. In October the Angels opted out of their lease, but a couple days ago they did sign a new lease that would keep them in Anaheim through 2020. So for now it appears they’ll continue to reap the benefits of the new right field wall. But in the coming years keep an eye on further renovations as well as potentially a new stadium.

The Chase Field Humidor

Now that we’ve touched upon the notable risers from last year, let’s talk about the elephant in the room: Chase Field. Chase, for the longest time, was a consistent hitter’s park. Paul Goldschmidt reaped the rewards of Chase Field for years and aside from him already being immensely talented, the park did help him become one of the best players in baseball. It was a power haven on the level of Coors Field. But then they followed in the footsteps of the Rockies and installed a humidor. After numerous complaints from pitchers about the grip of the baseball in Chase Field, the organization installed a humidor to improve pitching conditions. In brief, a humidor will decrease the “bounciness” of a baseball. Technically it’s the coefficient of restitution. The balls become heavier so they don’t fly off the bat as far or as fast and they won’t bounce as high or as far. This was obviously a mild nightmare in the fantasy baseball community and the results were real. Chase Field went from fourth in terms of home run rate in 2017 all the way down to 19th in 2018. But let’s take a closer look at the numbers because Chase Field got off to a horrendous start, but bounced back okay toward the end of the season.

Through the first dozen games played at Chase last season, the humidor was making its presence known. In 2017, Chase Field saw 31 home runs and averaged 12 runs per game through its first 12 games. In 2018 those numbers dropped to 23 home runs and 7.2 runs per game over the same span. Paul Goldschmidt didn’t his first home run in Chase Field until May 30th of last year. And of his 33 totals dingers from a year ago, only 12 came at home. Even through 24 games, Chase Field was still struggling to re-establish its reputation as a hitter’s park. Only 164 runs had been scored through that point to go with 44 home runs. As a team the Diamondbacks slashed .217/.299/.355 at home through 24 contests.

Roughly a year ago at this time Alan Nathan, a physicist and professor at the University of Illinois, predicted a 25-50-percent drop in home runs for Chase Field. The actual reduction turned out to be 20%, which falls outside of his prediction but it’s still a noticeable drop. But could this all have been simply because of a humidor? Kenny Kelly of SB Nation makes an intriguing argument that while the humidor had some of an influence on the decrease in home runs, it wasn’t the biggest factor. Kelly goes on to cite that the 2018 Diamondbacks were one of the weakest lineups in recent memory for Arizona. In 2017, they had Paul Goldschmidt and Jake Lamb each hit at least 30 home runs. Don’t forget J.D. Martínez smashed 29 home runs in just 62 games with Arizona that year. But in 2018, Arizona lost Martinez in free agency and Lamb was limited to just six home runs in 56 games. David Peralta did hit 30 home runs last year, but that could be an outlier of a season because he had never hit more than 20 prior to 2018. And don’t forget this season the Diamondbacks will be without Paul Goldschmidt so their offense could be even worse off than they were last year.

Not only was it Arizona’s weak offense, but the baseball’s were allegedly different in 2018. Ben Lindbergh notes how the seam height was lower in 2017 and 2016, which decreases the drag on a ball when it’s travelling through the air. This could potentially make the ball fly 10-20 feet further. After numerous pitchers voiced their displeasure with the ball including Justin Verlander, in 2018 there was an 8% decrease in home runs across all of baseball. MLB has denied ever juicing the ball or de-juicing the ball so it’s all hearsay at this point. If you truly care about my opinion (I know you probably don’t), I’m of the mindset that the balls were doctored. MLB knows that home runs sell tickets and chicks dig the long ball. Baseball was generating a ton of ratings when Sammy Sosa and Mark McGwire were crushing the ball in 1998 and then with Barry Bonds in 2001. But this time around it’s the baseball that’s juicing (see what I did there?), but perhaps MLB officials have done their part to once again adjust the balls to the pitchers’ approval.

Alas, the humidor may not be the only explanation for Chase Field’s drop in home runs. As with any trend there are always multiple factors whether it’s the poor lineup or a change in the balls. It wouldn’t surprise me one bit to see the home runs drop again in 2019 out in the desert.

Ballpark for Pitchers

Now on the other end of the spectrum there are obviously ballparks that cater to pitchers. These are the antithesis of Coors Field. Whether it’s wind patterns or larger dimensions, these ballparks just tend to suppress offense and home runs. You’ll always find the usual suspects as the most favorable pitcher’s parks: Marlins Park, Oracle Park (formerly AT&T Park), Citi Field, PNC Park, T-Mobile Park (formerly Safeco Field), Kauffman Stadium, and Petco Park.

Marlins Park in Miami was probably the best overall ballpark for pitchers last year, and they’ve actually made changes to the ballpark in the past to improve the offensive numbers. They’ve shortened the fences and moved them in over the past couple seasons and the front office even got rid of the gaudy home run statue in left-center field. I like to imagine that move was made so that hitter’s weren’t so distracted anymore. Yet offense was way down in this ballpark. If this was an open-air stadium the ball might travel further, but it’s still a pretty big stadium and don’t forget, prior to last season, the Marlins shipped off Giancarlo Stanton , Marcell Ozuna , and the 2018 National League MVP, Christian Yelich . Not to mention they traded Justin Bour last August and the Marlins are actively trying to move J.T. Realmuto . So while the ballpark caters to the gentlemen toeing the rubber, the Marlins are currently rolling out one of the worst lineups in baseball. In 2018 they were the only team in baseball to not score 600 runs. They were the only team in the previous three seasons to not reach 600 runs and they were dead last with just 128 home runs in 2018. The ballpark certainly won’t help them this season.

Comerica Park found itself in the same boat. Detroit’s ballpark was top ten in runs and home run rate in 2017, but regressed to below average results in 2018. Why? Well the team just wasn’t that good. Miguel Cabrera is getting older and missed significant time last season and J.D. Martínez was no longer on the team. And the offense suffered mightily. They hit the third-fewest home runs last season (135), scored the fifth-fewest runs (630), and they had the fifth-lowest team OPS (.680) in all of baseball. This is another case where I think the offense drove down the ballpark’s numbers.

Now for most of the parks mentioned in this section, they are traditionally pitcher-friendly. Parks such as Petco, PNC, Oracle Park, T-Mobile Park, etc. are all known for being pitcher’s parks. For the Oracle, the winds blowing across the field from McCovey Cove tend to keep balls in the park. Kaufmann Stadium, Citi Field, and Petco Park have always been difficult for home run hitters, but they’re more ideal for line drive hitters if they can put the ball in the spacious outfield gaps. I mention hitting the gaps in ballparks with larger outfields because a good offense can take advantage of this.

The Atlanta Braves who are entering their third season in SunTrust Park. SunTrust has nearly identical dimensions to Turner Field with a few alterations. Going from left field to center field the dimensions are almost the same. However, Turner Field was 390 feet from home plate to right field, but SunTrust is just 375 feet and not just that, but the park boasts a 16-foot high right field wall in front of what are the Chop House seats. If you ever get the chance to sit there, it’s highly recommended. The seats have cup holders that keep your beer cold for you, but I digress. The right field dimensions and the height of the wall make for a nice power alley. SunTrust saw great home run numbers when it initially opened, but they cooled off a few months later and in 2018, the smaller home run numbers continued. But it’s still worthy of consideration as more of a hitter’s park. In 2018 it ranked seventh in terms of runs being generated, but it was the fourth-worst park in terms of home runs. This is supported by the fact the Braves averaged less than a home run per game at their own ballpark (78 total), but still scored the eighth-most runs (391) at home because of their ability to hit their own gaps especially to their own power alley off the right field wall. It also helps that Atlanta had a much-improved offense with Freddie Freeman logging 162 games, but even he hit just 23 home runs last year. But the emergence of Ozzie Albies and Ronald Acuña certainly aided this organization and the Braves added Josh Donaldson to their lineup in the offseason. So don’t be too surprised to see SunTrust’s offensive numbers jump a bit based on personnel. This still can be labeled as a hitter’s park, but it tends to keep the ball in the park, which is decent news for fly ball pitchers.

To wrap it up, don’t become too enamored with ballpark factors when drafting players. Don’t downgrade Paul Goldschmidt because he’s now playing in Busch Stadium. He’s still an elite first basemen and should be drafted as such. Certainly changes in ballparks tend to help certain players, like Christian Yelich last season who went from Miami to Milwaukee. Players that were previously reliant on a certain ballpark can be downgraded a little bit, but a venue won’t be the end all be all. D.J. LeMahieu is transitioning from Coors Field to Yankee Stadium. That’s almost a lateral move for the second basemen and if he can stay healthy and find a spot toward the top of the order he could be a player than contributes 100 runs for your fantasy team. 

The Impact of Air Density

Air density is one of the biggest contributors in determining whether a ballpark caters to hitters or pitchers. Everyone knows Coors Field is arguably the best hitter’s park in all of baseball. That’s because of the elevation. It sits roughly a mile above sea level and features less dense (aka “thinner”) air.  Because of the less dense air the ball will naturally travel further. Now Coors Field isn’t the only ballpark at a high elevation, but it by far leads the pack by a wide margin.

Ballpark

Elevation (in feet)

Coors Field (Colorado Rockies)

5,211

Chase Field (Arizona Diamondbacks)

1,059

SunTrust Park (Atlanta Braves)

1,001

Kauffman Stadium (Kansas City Royals)

886

Target Field (Minnesota Twins)

840

Considering Coors Field sits 4,000 feet above all other ballparks, the air is significantly less dense. The thinner air in Denver decreases the resistance on batted balls, so they tend to travel farther. For the longest time the Rockies were the only team to implement a humidor for storing its baseballs. The general rule of thumb is storing them at 50% relative humidity and 70 degrees Fahrenheit. This will ultimately make the ball a little heavier and won’t be able to travel as far in less dense air. 

Humidity and temperature also play a role in air density, but not nearly as much as elevation. The more water vapor that is in the air, the farther a baseball will travel. Water molecules weigh less than air molecules so the more water vapor there is (aka the higher the humidity) the less dense the air becomes. The same is true for temperature. The warmer it gets, the less dense the air is. This is why you can expect balls to travel further in the summer as opposed to when the season starts in April. As temperature increases molecules speed up and spread apart and occupy a larger volume, this results in less air density.

All in all elevation is the biggest factor and with Coors Field sitting at least 4,000 feet over any other ballpark it will always have an advantage for hitters. Temperature and humidity will fluctuate throughout the season for all ballparks, but elevation is the only constant and Coors Field literally stands above the rest.

Wind Factors

Naturally wind is an intriguing factor to look at especially if you’re a DFS player. If wind is blowing out, that could help hitters. If it is blowing in, then it’s beneficial to pitchers. Certain ballparks may have their own unique wind patterns. Up until about 2013, Globe Life Park in Arlington, Texas was a power hitter’s dream. The ball just seemed to fly out of the ballpark with ease. Perhaps the heat and humidity factors mentioned above played a part, but from 2008-2012 Globe Life Park averaged over 200 home runs each year. Why? In the summer the wind would blow in from the South from the outfield. It would basically be “turned around” at home plate because of the closed in structure behind home plate and it would go right back out to the outfield. Now certain renovations to the stadium have decreased the wind blowing out, but it's still doing okay as a hitter's park. This will be the Rangers last season in Globe Life Park. Starting in 2020 they'll be moving into Globe Life Field, which will feature a retractable roof that would certainly take away the infamous wind pattern.

Oracle Park in San Francisco sits right on the bay so you’d assume a natural wind to be blowing in and yes that argument does make some sense. It’s only 309-feet to the right field foul pole, but the 25-foot-high wall takes a steep angle towards center field. Not to mention wind blowing in from the water in the summer tends to push balls back towards the power alley where fly balls tend to be caught. These are just two examples of 30 major league ballparks. Naturally on a day-to-day basis the wind and weather changes, so check the weather each morning to get a feel for how the wind is acting for each game to get a bigger advantage in DFS.

Size and Area

Major League Baseball is well aware that home runs translate to more viewers. It’s a tried and true statement, but “chicks dig the long ball” can be applied to all genders really. And franchises want to put people in the seats. So it’s no surprise that the league wants to bring more offense to the game. Since 2012 the Padres, Mariners, Mets, and Marlins have all moved their fences in to increase home runs. In the case of the Marlins they not only moved their fences in, but also put in shorter fences. As mentioned earlier, the Angels made a similar change to their right field wall prior to the 2018 season. While this is obviously a move to increase home runs it potentially leads to a drop in doubles and possibly triples.

But home runs aren’t everything for offense. In looking at some of the ballparks with larger outfields there are some that stick out as hitter-friendly parks. Coors Field, Chase Field, and Globe Life Park all feature some of the more spacious outfields in baseball and yet are still accommodating to hitters largely because of some of the factors listed above, but also more space in the outfield creates more alleys to drive the ball. As of 2015, there were eight ballparks measuring with at least 92,000 ft2 of outfield space. Of those eight, the three listed above (Coors, Chase, and Globe Life) are known more for being hitter friendly. Now some of the other ballparks with 92,000 ft2 in the outfield are Minute Maid Park, Kauffman Stadium, and Oracle Park. Interestingly enough those three ballparks are typically known for being better for pitchers.

However, there are also smaller ballparks. Fenway Park’s outfield measures in around 83,500 ft2 because of the heavily shallow left field due to the Green Monster that is over 37-feet tall. This becomes a target for right-handed hitters to try and hit one over the wall or at worst hit one off the wall and reach base safely. Somedownside to the Green Monster is that it can limit the slower power hitters to just long singles. Yankee Stadium is notorious for its short right field porch. By far the shallowest right field in all of baseball, at 24,200 ft2 it really plays as a hitter’s park. The Orioles (Camden Yards) and Reds (Great American Ballpark) both play in hitter’s parks because of the lack of foul territory as well as the hitter-friendly alleys in their shallow outfields.

Like the larger ballparks, the smaller ones feature a balance of hitter and pitcher parks. While Fenway Park and Yankee Stadium help out the bats, Tropicana Field, Minute Maid Park, and T-Mobile Park (formerly known as Safeco Field) aid pitchers. So while certain features of differing outfields may benefit hitting over pitching the overall size of each park has little impact. In this case, size may not necessarily matter.

Playing Indoors

Currently there are six baseball teams with retractable roofs: the Arizona Diamondbacks (Chase Field), Miami Marlins (Marlins Park), Milwaukee Brewers (Miller Park), Houston Astros (Minute Maid Park), Toronto Blue Jays (Rogers Centre), and the Seattle Mariners (Safeco Field). Most of these teams have varying weather-related concerns for why they have retractable roofs. Miami and Seattle both have heavy rain concerns. Houston sits right on the Gulf of Mexico so humidity is a concern down there. Toronto and Milwaukee need roofs to accommodate for the colder months at the beginning of the year. Lastly the Diamondbacks don’t suffer from the same concerns as the other teams, but intense heat in the summer is the reasoning for keeping the roof closed to keep the temperature comfortable inside for fans.

Tropicana Field is unique in that it is the only ballpark with a fixed roof so it will never open. The Rays will always play their home games indoors as long as they call Tropicana Field their home. The Trop is not without its controversy however. There are four levels of catwalks inside Tropicana Field. Now depending if you hit these catwalks in fair territory you could either be at risk of being out or you could be rounding the bases for a home run.

If you hit one of the higher two rings, highlighted with blue circles, the ball is still in play and it can be caught for an out. If a batter hits one of the two lower catwalks, highlighted with a red circle, in fair territory then it’s a home run. The catwalks and their attached masts and light fixtures face criticism on a regular basis as they occasionally impact a few games each year. Another unique feature of the Trop is the amount of foul territory. There are only two ballparks with over 30,000 ft2 of foul territory (The Trop and the Oakland Coliseum) and that extra space makes this ballpark more of a pitcher’s park because it gives the defense more room to catch foul balls. Add in the fact that the Rays play in a climate-controlled environment where wind and humidity don’t play a factor and this is a ballpark best fit for pitchers.

For the teams with the retractable roofs it’s important to understand that they can’t just open the roof at any given time. Obviously if it’s raining no team is going to open the roof up. In Miami, as lovely as it can be year-round, does experience its fair share of rain as well as excessive heat. But the roof doesn’t get opened as much as other ballparks open theirs. If the roof is open for 20 games it’s a miracle, which is a nice change of pace because back in 2012 they only opened the roof eight times. And all too often, fans won’t show up if the roof is open. For example, in 2018 the Marlins had 20 open roof games. However, they only opened the roof six times after June 12th because of the heat and humidity index in Miami’s hot summers. With the roof open, the Marlins hit just 14 home runs across 820 plate appearances. That’s a 1.70% home run rate with the roof open. Now remember, the Marlins offense was horrendous last season and the sample is really small if you take into account that they played less than a quarter of their home games in open air and 14 of those games were before the hottest days in Miami. In a larger sample size the home run rate was basically the same for Miami with the roof closed. They boasted a 1.74% home run rate across 2,239 plate appearances in 61 games, but of course this came with a depleted lineup and Marlins Park tends to aid pitchers more than hitters.

The Houston Astros and Minute Maid Park operate under similar circumstances. Houston experiences extreme heat and humidity levels during the summer. Because of this, the Astros keep their roof closed under the following conditions:

  • Threat of rain (obviously)
  • Threat of winds above 30mph
  • Temperatures below 65 degrees for a night game
  • Temperatures above 88 degrees for a night game
  • Temperatures above 84 degrees for a day game

Also keep in mind, under these conditions the roof will remain closed. But it’s not a guarantee that on a 72-degree night in Houston, the roof will be open. At that point, it’s at the organization’s discretion. Because of these conditions, Houston kept the roof shut for 70 games last year. Still, with the roof closed the Astros touted a 3.21% home run rate with 83 home runs in over 2,500 plate appearances. Clearly they were a more potent offense than Miami considering they made yet another deep postseason run. In a much smaller sample size of 11 games, the home run rate was just 2.29% but keep in mind it’s not a fair comparison since over 85% of their home games were played with the roof closed.

So to see if there actually is an impact on open air or a closed roof it’s better to look at larger or more even distributed sample sizes. Fortunately we can look at two ballparks for this comparison: Rogers Centre and Miller Park. Just North of the border in Toronto, the Blue Jays and their fans certainly love to open up the roof as often as possible. In 1,478 plate appearances with the roof open, the Blue Jays hit 57 home runs for a 3.86% home run rate. With the roof closed, the number jumps slightly up to a 4.04% home run rate. Truth be told, they logged 43 fewer plate appearances, but just one home run in a closed roof setting. So it’s not a terribly drastic jump but it’s a pretty big change from 2017. The open-air rate was roughly the same at 3.81%, but the closed roof rate was 3.64%. Keep in mind that Toronto experiences a slightly longer cold season than most MLB cities. Because of this they don’t even get to test the roof out until early May and the first open air game may not happen until mid-May and sometimes Toronto doesn’t open the roof until June.

Miller Park is similar to Rogers Centre in that it typically won’t have any games in April with the roof open. It’s too cold and the state of Wisconsin could still be dealing with the occasional snow at that time. So with the roof closed, the Brewers logged a 3.71% home run rate in over 1,200 plate appearances. Miller Park saw a slight uptick in home runs with the roof open at a 3.93% rate, which isn’t incredibly notable. Miller Park has been a better ballpark historically in open air even before the improved lineup they had in 2018. For that reason, it’s worth stacking Miller Park bats on a day when the roof is open. The Brewers twitter account and Milwaukee beat writers usually do a pretty good job of notifying followers a couple hours before game time whether the roof will be open that night.

But keep in mind it’s not necessarily the roof being open that has a great impact on the air. Sure, it certainly helps in Milwaukee, but the importance is that the ball travels further in warmer weather when the organizations tend to open roofs more. The ball wouldn’t travel as far in colder weather at the start of the year. Fantasy baseball players typically don’t see as much offense in Coors Field or Great American Ballpark until we reach the warmer months of the season.