Verlander has the most impressive combination of velocity as well as accuracy, though he still can't spot his fastball with any consistency. Verlander's fastball can hit triple digits, and while he doesn't often hit those numbers in games, his fastball still typically sits in the upper 90's. That velocity alone enabled Verlander to cruise through the minor leagues, but for Verlander's fastball to become truly dominating, he'll need to develop the accuracy to hit specific spots in the zone.
Zumaya's fastball has much the same velocity, and like Verlander, Zumaya can also get up to 100, even touching 102 MPH before. However, Zumaya's fastball typically sits around 95 or 96, but even at that velocity, he doesn't possess the control to hit any particular spot. Possibly Zumaya's biggest fault that he'll need to correct before he can become a truly dominating force at the major league level is that he needs to harness his fastball – too often, Zumaya will allow his fastball to ride up in the zone, which causes two problems. First, leaving the ball up in the zone makes it much more hittable and allows good fastball hitters to turn it around. Second, the ball up in the zone means lots of balls, forcing Zumaya to work deep into counts to record outs, and in turn forcing him to reach his pitch limit early in games.
Next up is a pair of relief prospects, both of whom could find themselves in the Tigers' bullpen; Kevin Whelan and Eulogio de la Cruz.
Whelan burst onto the scene less than a year ago after the Tigers selected him in the fourth round of the draft, and he immediately made his presence felt. Whelan can't hit triple digits like Zumaya or Verlander, but still sits comfortably in the mid 90's (though by the end of '05, he was only hitting 92, likely due to pitching a full college season and then jumping immediately into the pro game). What Whelan doesn't have in velocity though he gains back with control and movement. Whelan can not only hit his spots, but his fastball has good, late bite on it that makes it very tough for hitters to make solid contact with.
Whelan has good late, movement, but de la Cruz relies solely on straight heat. His fastball sits in the 96-97 MPH range, but much like Verlander and Zumaya, it's not uncommon for de la Cruz to dial it up into triple digits. While two years ago he was very much the close his eyes and let it rip type, each of the last two seasons he has seen excellent development with his control (along with a willingness to use his off-speed pitches in game situations). De la Cruz still doesn't always hit his spots and did still issue 40 walks in less than 100 innings of work, but he continues to miss bats with his heat, and much like the old saying ‘you can't teach height', you also can't teach his kind of velocity.
Finally, we move on to a pair of pitchers that can bring heat, they just can't always control it, or can't stay in the game long enough to put it on display. Both Humberto Sanchez and Jay Sborz have been notable acquisitions for the Tigers (Sborz a second round draft pick, Sanchez a draft-and-follow that was given first round money). And both happen to possess very solid fastballs.
Sanchez has been one of the most complicated prospects in the Tiger organization, as he possesses so much talent, yet at the end of the season his numbers never seem impressive and he inevitably had injury and stamina problems. That doesn't change the fact that Sanchez has a very good fastball that typically sits in the mid 90's. What's more, much like Whelan's late bite, Sanchez has excellent sinking action on his fastball that makes it increasingly difficult to make contact with, considering it's already coming in at a high velocity. His lack of athletic ability is often a concern and is often cited as the principal reason why Sanchez can't find any control, rhythm or consistency in his mechanics, but the raw potential makes Sanchez a very dangerous potential weapon.
Finally we come to Jay Sborz, yet another frustrating pitcher for the organization. Only unlike Sanchez, Sborz hasn't even been able to put together for short stretches. In his favor, Sborz is still just 21 years old, has a mid 90's fastball and a frame that is still filling out. On the other hand, the Tigers couldn't even keep Sborz in the bullpen for West Michigan, as his struggles were too extensive for them to keep him as an effective reliever. His fastball has plenty of movement and could continue to add extra MPH, but all of that is immaterial if Sborz can't find the plate with any consistency.
All in all, the Tigers have quite a few live arms, many of which have used their talent to place themselves among the top prospects in the system. The key for all of them though will be to learn to harness their impressive velocity and eventually turn that into big league success.