The season is pretty much in full swing now with fifth starters finally making their first starts of the year this week. However, the minor leagues have just gotten going in the upper levels while the lowest levels haven’t yet started. Teams have made a bunch of call-ups already for prospects making their debuts and some broke camp with their respective major league teams. This week we’re focusing on the prospects that are worth keeping an eye on this year in the National League division-by-division.

NL East

Mike Soroka (ATL) – We all know that the Braves have a heap of young arms in their system and Soroka is the best one of the group. He got a taste of the majors last year before a shoulder injury ended his season early. Soroka is still just 21 years old and so they will take it easy with his recovery from the shoulder issue that flared in spring training as well in March. Prior stints in the minors though have borne fruit as he posted a 2.75 ERA, 3.19 FIP, 7.32 K/9, 1.99 BB/9, .228 BAA, and 1.09 WHIP in 153 innings at Double-A Mississippi. The 6’5”, 225 lb. righty uses a three-pitch mix for a mid-90s fastball that’s more of a sinker than fastball, a sharp slider that can morph into a power curveball, and lastly an above-average changeup that fills the strike zone consistently. Even though he has the body of a frontline starter and creates a downhill plane like we expect from guys of his size, the three-pitch mix and the reduced strikeout rates put him as more of a number three starter type rather than an ace or number two starter. He should come up in the second half of the season once he gets some healthy innings under his belt and help the Braves rotation down the stretch in a competitive NL East race.

Monte Harrison (MIA) – Harrison was a big piece in the Christian Yelich to the Brewers trade back prior to the 2018 season. The 6’3”, 220 lb. 23-year-old outfielder has some intriguing tools for sure and is a nice power-speed combo guy working on something in Triple-A New Orleans. In 2017, split between the Brewers’ A-ball and High-A affiliates, he hit .271/.350/.481 with 21 home runs, 73 runs, 67 RBI, and 27 steals. In 2018 he backed that season up with a .240/.316/.399 line in Double-A Jacksonville for Miami with 19 homers, 85 runs, 48 RBI, and 28 steals in 136 games. The hit tool is still evolving but the power and speed are evident. The outfielder made improvements and adjustments to his swing and approach at the plate in the Arizona Fall League in 2018, namely with reducing his leg kick, and if those adjustments hold his average could improve along with approaching 30-30 upside in a full season. Harrison could be up in the middle of the season if he starts well in his first taste of Triple-A given how bad the Miami offense has been to start the year.

Tanner Rainey (WAS) – In a rare Tanner-for-Tanner swap this offseason, the Reds and Nationals dealt Rainey for Roark with Rainey winding up in the Nation’s Capital. Rainey was taken in the 2015 draft by the Reds in the Competitive Balance Round B at 71 overall, and after working up his innings he was switched to a bullpen piece, which was the plan all along. Rainey features a great mix of power stuff in a 70-grade 100 mph fastball and a hard, power slider, that are both swing-and-miss pitches at an elite rate. The changeup is the third offering and still just a pitch that he can use against lefties on occasion. Once he was flipped to a reliever to start the 2017 season he was a fairly dominant bullpen arm with a 2.92 ERA, 1.08 WHIP, .141 BAA, 13.3 K/9, and 36.5-percent K-rate in 114 innings between 2017 and 2018 and between High-A, Double-A, and Triple-A. The part of the stat line I left out was his 5.4 BB/9 rate in that span which is far from spectacular especially for a reliever with swing-and-miss stuff. If he can better harness his arsenal and improve the command and control he could be a piece in improving the woeful Nationals bullpen.

NL Central

Dillon Maples (CHC) – Maples is a very similar to the guy we just discussed in Tanner Rainey . Maples has had a taste of the majors previously, but it hasn’t exactly gone will from an ERA or walks standpoint. The only way it did go well is with regard to his 20 strikeouts in the 10.2 innings. Maples has a plus-plus fastball and a plus-slider that he uses to strikeout hitters, but the problem is his 30-grade control leaves a lot to be desired in the walks and WHIP department especially for a reliever. Chicago has had rough sailing the first couple of weeks of the season in the bullpen department, mainly due to injuries to key guys like Brandon Morrow and Xavier Cedeño and to a degree Pedro Strop . If at Triple-A, where Maples currently is, he can show anywhere close to passable command, the north siders could use his arsenal coming out of the pen and racking up those late innings strikeouts like he did between his 104.2 innings in the minors from 2017-19 with 182 strikeouts.

Nick Senzel (CIN) – The saga of Senzel continues to develop in Cincinnati into it’s third year now. He was drafted as the second overall pick in the 2016 June draft as the best college player in the draft and the best bat in that draft overall. Since then though the main talk surrounding his development has circled around injuries, both his and injuries on the major league roster. It’s been clear since the second-half of 2017 when he was at Double-A that Senzel was ready for the bigs but there wasn’t really a spot for him and the Reds didn’t want to start the clock on his control at that point. Then came 2018 and the injury to Eugenio Suárez early in the year that should have cleared a spot for Senzel but again the Reds didn’t want to start the clock on him and shortly after not calling him up, the top prospect had a bout of vertigo in May and then broke his finger in June that ended his season. In the short time on the field at Triple-A in 2018, Senzel slashed .310/.378/.509 with six home runs, 25 RBI, 23 runs, and eight steals in just 44 games at Louisville. In spring training in 2019 Senzel was worked out at second base and in centerfield but was sent to Triple-A to start the year to work on defense, is what the club said, and wasn’t called up when Scooter Gennett went down for 8-12 weeks. At some point in 2019 his bat will be too hard for the Reds to keep in the minors and he will likely be up in the second half of this season with perhaps multi-position eligibility to boot.

Mitch Keller (PIT) – Keller has risen up the prospect charts to be one of the top pitching prospects in the minors and is the Pirates top prospects overall. The 6’2”, 210 lb. right-handed pitcher is now 23 years old and getting his second taste of Triple-A to start the 2019 campaign after pitching 52.1 innings in Indianapolis to finish off 2018. An arsenal of a sinking 93-96 mph fastball that routinely touches 98-99 mph, an 11-to-5 curveball, and an improving changeup that grades out as a major league average offering. In 2018 as he pitched 138.1 innings across Double-A and Triple-A he combined for a 3.51 ERA, 1.28 WHIP, .233 BAA, 8.65 K/9, 3.51 BB/9, and a 22.9-percent K-rate in 24 starts and a 12-4 W-L record. His durability, frame, and stuff make him a candidate to be a frontline starter in Pittsburgh but ultimately, he will likely top out as a number two or three starter with the lack of a fourth pitch in the arsenal. The Pirates rotation is pretty set at the moment but in the second half, Keller should be one of the first mid-season call-ups in the majors.

NL West

Yoan López (ARI) – If you were paying attention to the preseason podcasts from the Fantasy Alarm team, this guy’s name being included in this piece wouldn’t be a surprise to you. Lopez is a reliever prospect for the Diamondbacks who’s had an interesting path to the majors. He was signed out of Cuba in 2015 to the tune of $8 million but didn’t really find success until he was moved to the bullpen in July of 2017. Since then he’s been nearly lights-out moving from High-A to Double-A and up to the majors in two different stints. Lopez uses a 97-99 mph fastball with a high spin rate and an 84-87 mph slider with two-plane break and even higher spin rate as his main two strikeout pitches. The third pitch is a changeup that he has to develop confidence in because it could be a third swing-and-miss offering from the 6’3” lanky righty. The strikeouts have definitely been there as he struck out opposing batters at a better than 33-percent clip over 70.2 innings in 2018 split between Double-A and MLB. Lopez is a candidate to close out games of the Diamondbacks this year and was the talk of the staff in spring training as his stuff had all sorts of movement on it which is important in late-inning arms.

Josh Fuentes (COL) – Fuentes is a new addition to the piece this week after his call-up over the weekend for Colorado to play first base. He went undrafted in the 2014 draft and Colorado took a shot on him because of his pedigree as he’s the cousin of Nolan Arenado . The faith they put in him, and some adjustments he made following the 2015 South Atlantic season, have paid dividends as he’s hit better than .300 three years in a row now including his 2018 Pacific Coast League MVP winning campaign. The power might not be there as he’s hit a combined 29 homers over the past two years in Double-A and Triple-A but neither are the strikeouts with a sub-20-percent K-rate in that span as well. Hitting for contact with a stroke that can generate 15-20 home runs a year and having enough speed to steal 5-10 bases a year gives Colorado another piece to try and solve their first base problem with. Ryan McMahon is injured, as is Daniel Murphy , and there isn’t a willingness to put Ian Desmond back in the infield so it will be Fuentes manning first base for the foreseeable future. He may do enough to make himself a valuable member of the roster as well.

Logan Allen (SD) – The Padres’ pitching prospect that was the talk of spring training was Chris Paddack and for good reason, but Allen has the stuff to join him in the San Diego rotation pretty soon as well. Allen uses a four-pitch mix from the left-side of the pitching rubber to keeper hitters guessing and striking out as well. A fastball that sits comfortably between 92-94 with great late life keeps batters from squaring it up frequently as does his aggressive placement with the pitch in the zone including on the inner half to righties. The 60-grade changeup is his best secondary offering and plays beautifully off of his fastball with both depth and fade working to his advantage. He does possess both a slider and curveball, but both are still improving, and the former is better than the latter at the moment. Allen split 2018 between Double-A and Triple-A while being on the mound for 148.2 innings and posting a 2.51 ERA and a 151:51 K:BB ratio. He isn’t the dominating guy that Paddack and some others are in their system but that doesn’t reduce Allen’s upside any less as he has the goods to be a number two or likely number three starter for San Diego starting in the middle of this year.