Week One of the fantasy baseball season is in the books and man does it feel great to have baseball back in our lives. Over the course of this week, I have certainly been both excited and disappointed with the performances of some players; and while it really has only been one week, it is never too soon to start looking at which players are worth buying into and which players you should be looking to move on from while the iron is hot.

Glossary

FIP- Fielding Independent Pitching

SIERA- Skill-Interactive ERA

BABIP- Batting Average Balls In Play

Buying

Robbie Ray (SP, ARI) - Like many, I was high on the prospects of Ray this offseason after he finished 2016 with an impressive 218 strikeouts over 174.1 innings. The downside with Ray came with his 4.90 ERA and 1.47 WHIP but for us sabermetric nerds we saw that he owned a decent FIP of 3.76, a 3.86 SIERA and a BABIP against of .352 which indicates he was much more unlucky last year than he was pitching poorly. Heading into this season, much was made about Ray taking on a new approach on the mound. Mostly, he understood that he can’t just rely purely on his fastball to get major league hitters out all the time and while striking out hitters is certainly important, he understands that a new approach can help make him much more successful on the mound. That new approach was on display during his first start of the season against the Giants and while he did allow three runs over 5.2 innings the Giants also only got three hits off him. During this start, Ray threw his fastball just 38-percent of the time which is a big drop from the 53-percent fastballs he threw in 2016. With the drop in fastball usage came an increase usage in his slider which he threw 34-percent of the time after using that pitch just 16.3 percent of the time last year. The increased usage in breaking balls will keep hitters off balance and Ray’s natural strikeout ability could benefit even more because of it. I expect Ray to possibly waver a bit over the first few starts while he gets more comfortable with this new approach but I do not think it will take too long before we see him finally reaching that potential.

Wily Peralta (SP, MIL) - Many might not realize it but Peralta finished the 2016 pitching better than at any point in his major-league career, owning a 2.92 ERA, 3.2 K/BB ratio and a .281 BABIP against. This comes after a horrible first half which likely caused him to fall off the radar of every fantasy player on earth as he owned a 6.68 ERA over the first few months of the year. His early struggles found him removed the rotation and demoted to the minor leagues. An injury in the Brewers rotation saw Peralta get another shot however, and he took full advantage of it. When considering what could have sparked Peralta’s second half resurgence one of the first things I noticed was an increase in his fastball velocity. For comparison, in 2014 Peralta had a career year, going 17-11 with a 3.53 ERA. In 2014 Peralta’s fastball velocity averaged 96.4 mph. In 2015 and the first half of 2016, in which Peralta really struggled, his average fastball velocity was 95.1. Believe it or not a slight dip in velocity like that is in fact a big deal, especially for a pitcher who relies heavily on the pitch. Upon his return from the minors last season Peralta’s fastball velocity had increased to 96.4 mph and in his first start this season his fastball averaged out at 96.5 mph.

Average Velocity     
DateFourseamSinkerChangeSliderCurve
201496.496.585.086.20.0
201595.195.184.083.30.0
2016 H195.395.385.885.50.0
2016 H296.496.285.684.676.7

Another leading factor to Peralta’s increased success in 2016 very well could have been the increased use of his slider. Prior to being recalled Peralta was throwing his slider just 28-percent of the time. Once he returned from the minors Peralta was throwing his slider 36.7-percent of the time. The mix in pitches likely kept hitters off balance and thus lead to increased effectiveness. Peralta is still just 27 years old and was once considered a top prospect so the talent is certainly in that right arm of his and maybe in the second half of last season we finally saw everything click. It’s unlikely was Peralta drafted in many leagues and even more unlikely that anybody picked him up as a streaming option against the Rockies in his season debut so check the waiver wire if you are looking for a speculative add in mixed leagues and those in NL-only formats should look to add him as well even if you want to take a wait and see approach.

Selling

Steven Souza (OF, TB) - Souza is off to a hot start with the Rays this season, hitting .370 with three runs, one home run and six RBI over eight games. Souza has spent the previous two seasons with the Rays where he has managed to put up pretty regular numbers, averaging around 58 runs, 17 home runs, 48 RBI and eight stolen bases over 115 games. Those numbers over the last two seasons have also come with a career strikeout rate of 32.8-percent and a walk rate of just nine percent. And there-in lies my skepticism to the start that Souza is off to. Through eight games Souza has struck out just three times while having already walked six times over 33 plate appearances giving him an 18.2-percent walk rate and a 9.1-percent strikeout rate. These are just not numbers that will hold up as Souza, even as a minor-league player consistently struck out around 25-percent of the time. Players do certainly go on hot streaks and Souza does have the upside of a of a player who can go for 20+ home runs and 10+ stolen bases but the batting average is going to drop over 100 points by seasons end and now would be the time I would look to move on from him before that inevitable slump happens.

Ryan Zimmerman (1B, WAS) - When healthy, Zimmerman has been a productive hitter throughout his career. The problem however is the fact that in his 12-year major-league career Zimmerman has played more than 140 games just six times. Since the start of the 2014 season Zimmerman is averaging just 90 games per season. At 32 years old it seems unlikely that he will now start to stay healthy for a full season and that is quite a shame because he is an effective fantasy player. Even over the last two seasons he has averaged 50 runs, 15.5 home runs and 59.5 RBI over 110 game which is pretty solid given the playing time. To start the season Zimmerman is hitting .400 with six runs, three home runs and six RBI. We know the potential to hit 25 home runs is still in his bat but his health will forever be a concern. If you own Zimmerman and want to ride out his hot streak I do not blame you but I would also be actively looking to see what I could get for him on trade market in your particular league because I do feel it is just a matter of time before he finds himself on the disabled list.