An exciting young arm in the Padres' system, Miller already has the fastball to dominate – hitting 93-95 MPH and touching 96 MPH. Armed with a good feel for pitching, he sets hitters up well and takes them out when he has the chance.
Miller is still in the developmental stages with his changeup and curveball but should reap the rewards when those pitches become quality major league offerings. His easy delivery and repeatable mechanics lend credence to his top billing.
It isn't just the speed of Carrillo's fastball that has him so high on the list but also its movement and his ability to locate the heater at will. So, while there are more powerful arms in the organization there are few who has more effective fastballs.
Carrillo sits 91-94 MPH with his fastball and can zip it in up to 96 but the late movement it generates and the fact that he has established a quality assortment of off-speed pitches make it seem even livelier and faster.
3. Simon Castro
As far as pure power goes, Castro may take the cake. He works in the 92-95 MPH range and can hit 96-97 MPH with the heat. But, he is also raw – more so than any other pitcher mentioned.
First and foremost, Castro has to work on consistency with his first-pitch strikes and staying ahead of the hitter. Once he establishes that and betters his slider, the fastball will become deadly as a strikeout pitch.
With a solid assortment of pitches, Oyervidez' fastball is much more effective because of excellent secondary pitches. His fastball has good movement and sits in the low-90s, hitting 94 MPH.
While he has a wicked fastball, it is the inconsistency outside of the strike zone and lack of consistent command that puts Oyervidez below his counterparts. Control would put him among the elite because of his full repertoire.
Once he cleans up his mechanics, Menchaca could move into the upper echelon of this list. He has a heavy fastball with late pop, topping out at 94 MPH right now. He has a tendency to work from behind in the count, taking away the effectiveness of the heat.
With a more consistent approach and the development of his secondary pitches, Menchaca could add a few ticks to the heater and increase its effectiveness.
Also in consideration (alphabetical):
He is on par with Miller with his fastball and should see bigger dividends as his changeup continues its ascent.
He has the fastball, it has life, and he can throw it for strikes. He simply lacks the killer instinct to make it a dominating pitch.