Rondon's fastball is one of the best in all the minor leagues. In my personal observation over three games last year, Rondon consistently sat at 99-101 mph and touched 103 on multiple occasions. Even when he took some off to find the strike zone or lower his arm slot, Rondon still hits 95-96 mph and can blow his fastball by any hitter at any level. It is a truly elite pitch that earns the vaunted 80 on the 20-80 scouting scale.
Robertson and De La Rosa were both finds in the last couple of years for the Tigers. They are both big guys with long arms and legs and plenty of velocity on their fastballs. While Robertson sat 93-94 during his starts with Connecticut last year, he can dial it up to 97 when he needs to and in short bursts. Like Robertson, De La Rosa sits in the low- to mid-90s but dialed it up to 98 mph at times last summer.
The Tigers have been waiting for Casey Crosby to remain healthy and reach the big leagues since drafting him in 2007, and he finally arrived in the big leagues for a short time last year. From the left side, he still flashes 95-96 mph heat with tremendous life.
Melvin Mercedes was a hot name a couple of years ago and he slipped off the radar after undergoing Tommy John surgery, but he was back in 2012, showing plus to plus-plus velocity, including the ability to reach 96 on the gun.
Ramon Lebron has been a consistent entrant to this list in the past, and while he rarely touches 97-98 mph now, he was still showing 95-96 mph velocity from a lower arm slot in 2012. Putkonen burst onto the big league scene last year and while his fastball gets a little true at times, he shows mid-90s heat.
Endrys Briceno already has present velocity, sitting in the 91-93 range and hitting 96 mph when he reaches back with his four-seam fastball, but he also has a ton of projection. Briceno still has a rail thin frame with excellent height, and any additional strength could mean more gains with the fastball. Castro is very young but has excellent projection and some scouts believe he could "throw very hard" at his peak. Manzanillo and Montero made this portion of the list last year as well and they still flash premium velocity but don't sit there because they are extremely raw.
Juan Alcantara (RHP)
Will Clinard (RHP)
Julio Felix (RHP)
Brenny Paulino (RHP)
Chad Smith (RHP)
Tyler Stohr (RHP)
Jake Thompson (RHP)
Jose Valdez (RHP)
Drew VerHagen (RHP)
Several additional prospects were in the mix for this list, including former entrants like Brenny Paulino, Chad Smith and Tyler Stohr, all of whom still show good velocity. Jose Valdez could be the big riser from this list, showing the occasional mid-90s fastball and the potential to sit at 95-96 with more consistency. Drew VerHagen and Julio Felix, both drafted last year, can touch 95 mph when they need it.