The farthest away but the most electric arm this side of the Mississippi. The Padres have said on numerous occasions that Juan's arm is the fastest they have ever seen from a left-hander.
The question is whether he has the mental makeup to take the lessons he is learning to the field. He can dial it up to 99 MPH and it looks easy but is on a fastball/changeup diet until he shows progression and consistently throws strikes.
2. Simon Castro
The right-hander was dealing at 94-96 MPH at the Padres' Instructional League and that might just be a taste of what he can do.
Castro needs to work on throwing strikes and his secondary pitches but has true number one potential – a product of an improving Dominican program.
He has a bulldog mentality and his mechanics are cleaning up – the result has been improvement in every phase of the game and a fastball in the mid-90s.
Menchaca works from behind in the count too much but has largely avoided trouble. If he can pinpoint those first pitch strikes he could be deadly and has the grit to be a frontline start in the majors.
4. Drew Miller
Impressive arm action and mechanics, Miller is a future No. 2 waiting to happen. He isn't as far along as the next name on the list but has a slightly higher ceiling.
Miller dials it up to 95-96 MPH and is developing a solid repertoire of secondary pitches. Once the changeup is commanded and comes in slower, Miller could be devastating.
5. Aaron Breit
Blessed with all the intangibles, Breit is a heady pitcher that challenges hitters on the inside part of the plate.
He has a mid-90s fastball and good feel for a changeup but doesn't have quite the movement of Miller. Still, his polished approach makes him a solid bet as a future No. 2.
Also in consideration (alphabetical):
Health pending, Carrillo is worth the hype. He has incredible movement on his pitches and keeps the ball low.
Slowed his fastball down to 94-95 MPH and saw impressive results and more strikes. He could rise up the list.
He has an incredible assortment of plus pitches and if he can keep the walks down he will be a major leaguer for a long time.
It is hard to pick up his ball and when healed from some elbow soreness he could spike up all lists.
He really has special talent and a solid assortment of pitches – he just needs to throw his game and work in more changeups.