Each week in this report, I’ll be monitoring the performances of MLB rookies. I will emphasize those rookies who put up especially positive performances, while also taking care to mention rookies who are underperforming expectations. In both cases, I will dig into the underlying stats and attempt the difficult task of projecting forward.
Rookies are typically more unpredictable than their more experienced colleagues, and can, therefore, be a source of great profit in fantasy baseball, or great frustration. Stay tuned to this space every week to find out which newbies should be in the mix for your squad. Check out last week’s Rookie Report to keep up to date on all the hottest youngsters.
Stats are current prior to Wednesday’s games, and, as noted in week 3, any quoted Statcast numbers are directly from Baseball Savant.
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Quick Update: Ben Gamel
When last we visited Ben Gamel, I noted that his K% and BB% were likely to decline, which they have, to respectable marks of 24.3% and 8.7%, respectively. I also noted that his .432 BABIP was unlikely to hold up given his pedestrian batted-ball profile. His BABIP has, in fact, risen to .435 despite his Statcast xBA falling to a mediocre .259. His park and horizontal angle adjusted xAVG according to xstats.org is .286, suggesting that his all-fields approach may be helping buoy his average a bit. Indeed, his combined opposite and center field batted ball percentage is in the top 15% of hitters. Nonetheless, there is almost no way Gamel can sustain a batting average over .300, let alone one over .330. In nearly two months since his first profile, he has only hit two HR and stolen two bases. While he has seemingly retained a starting role ahead of Guillermo Heredia, Gamel’s expected regression and lackluster counting stat production make him a sell-high candidate in most leagues.
Raimel Tapia (OF – COL)
Ranked the No. 46 prospect according the the Expert Consensus Rankings and 69th according to Bobby Sylvester, Tapia’s promotion was largely overlooked due to the ongoing promise of a David Dahl return as well as the presence of established veterans Carlos Gonzalez, Charlie Blackmon, and Gerardo Parra. DL trips for Parra, Gonzalez, and Ian Desmond, along with the very slow recovery of Dahl have granted Tapia near-everyday playing time for the surprising Rockies, and he has rewarded them with a .313/.360/.482 line, two homers and three steals in 89 plate appearances. Given his home park, it is not surprising that his .313 AVG and .359 wOBA significantly outpace his .237 xBA and .278 xwOBA. Because Coors Field is such a favorable environment, it would not be surprising to see Tapia’s average remain close to .280, especially given his high-contact approach. Since speed was more of a calling card for Tapia than power in the minors, owners should expect more steals than homers going forward. In the end, Tapia could provide a 10 HR, 15 steal pace with a solid batting average and good value from a low-investment player. As with most fringy Rockies, Tapia is best deployed in daily move leagues in favorable home matchups.
Adam Engel (OF – CWS)
Part of the current White Sox youth movement, but not necessarily their rebuilt future owing to his non-existent prospect status, Adam Engel is a 25-year-old former 19th-round pick whose carrying tool is his blazing speed. With a .242 ISO, he showed surprising pop at Triple-A to start the season and has thus far impressed in the majors with two homers and 4 steals. However, Engel’s 79.4 mph average exit velocity place him very near the bottom of the league, alongside fellow rabbits Billy Hamilton and Jarrod Dyson. His resultant .208 xBA and .279 xwOBA suggest that his overall batting line will stabilize well below his current pace and well below average. In order to retain any value, Engel will need to steal a lot of bases. While his 65 steal 2015 season suggests he is capable, I would not bet on it, especially given his tendency to strike out in over a quarter of his plate appearances.
Luis Castillo (SP/RP – CIN)
While not quite as low-end a prospect as Engel, ranking between 100 and 200 on both the ECR and Sylvester rankings, Castillo has not received much in the way of hype in the Cincinnati system. What he lacks in pedigree, he makes up in arm speed. At 97.9 mph, his fastball velocity ranks 16th out of 446 players with at least 100 fastballs thrown and second among starters behind Noah Syndergaard. Castillo also has a slider and changeup that each generate over 20% whiffs, and his overall 14.2% SwStr% is stellar. Unfortunately, in fitting with the rest of the Reds staff that owns a shockingly poor 0.1 WAR, Castillo has not had success preventing runs. His 4.41 ERA and 1.71 WHIP in three starts do not inspire optimism, but his 12.12 K/9 is intriguing, especially given his swinging strike rate and his strikeout rate spike in the minors to start the year. Castillo has shown good control throughout much of the minor leagues, which suggests that he can improve on his 4.96 BB/9. In fact, apart from his five walk debut in Washington, he has not been especially wild. Owners can perhaps forgive Castillo for his nine hit, four earned run outing at Coors Field, given the nice 8/1 K/BB total. An upcoming matchup on Saturday at Chase Field is similarly unfavorable, so owners are best off monitoring Castillo until after the All-Star break, but he may be a sleeper starter going into the second half.
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Andrew Dominijanni is a correspondent at FantasyPros. For more from Andrew, check out his archive and follow him @ADominijanni.
