The Miami Marlins would really like for Nathan Eovaldi to develop into at least a mid-tier starter for the Fish. The presence of two guys, including Jose Fernandez, from the incumbent staff alongside the myriad of pitching prospects coming up the pipeline could make for one of the best rotations in baseball if all pans out the Marlins' way. The Fish have long desired to build through pitching, and the development of Eovaldi can go a long way to accomplishing that.
But the Marlins are counting on the development of a player who has shown one tangible improvement and, surprisingly enough, not much else. The Fish believe things will work out their way developmentally, but what if the pessimistic viewpoint is right and Eovaldi never progresses?
The Pessimist's Case
The case the pessimist has on Eovaldi and his potential for stalled development lies in the weaknesses we mentioned just last week.
Eovaldi's problem is pretty self-evident: he cannot face lefties with his current arsenal. The curveball he has worked on has barely made a dent against lefties, and he essentially abandoned it last season in favor of more fastballs. The slider has been effective last year versus left-handers, but he threw it fewer times than he did the curveball. The numbers, however, do not lie; the three-pitch arsenal just does not work versus lefties.
A pitcher who throws primarily a fastball is not a promising trend either. Since the Pitch F/X era started in 2007, the pitchers with at least 400 innings and the highest percentage of fastballs thrown usually fared poorly as starters. The top ten list includes two good pitchers (Clayton Kershaw and Jordan Zimmermann) who either have fantastic secondary offerings or a offer a strong blend of off-speed pitches to compensate. The top ten also includes casualties like Daniel Cabrera, John Maine, Oliver Perez, and Jonathan Sanchez. Relying on the fastball too heavily is a bad idea in the big leagues.
This may not be a problem if Eovaldi's fastball and game develop as the optimistic viewpoint would point out. If his fastball made him into a star, then Eovaldi could probably get away with his pitches against lefties. But unfortunately, last year's performance showed no evidence of improved performance for the fastball over 2012, when Eovaldi was throwing closer to 94 mph than 96. From the Pitch F/X scouting report:
In terms of placing the ball in the strike zone and getting hitters to swing and miss, the fastball failed to improve in any meaningful fashion. Perhaps the change in BABIP was real, but in a single season of work, it is difficult to separate out the noise in that category. The fact that the whiff and called strike numbers remained essentially identical seems more telling, and if the much-hyped velocity jump yielded no added benefit, then Miami may not have a potential ace on their hands.
The Pessimist's Projection
The Marlins are hoping that Eovaldi can beat out the poor expectations of a pitcher of his type. The team would like for Eovaldi to either figure out those pitches or improve the fastball. If neither of those things happen, you can easily see him dropping back to his 2012 rookie-season levels. An ERA in the mid-4.00's, much like the 4.36 mark he put up in 2012, is within expectations and would be quite a disappointing step back for Marlins fans.