When the Tigers drafted Kyle Sleeth third overall, they expected him to move through the system quickly. Because of a heavy college workload though – including pitching for the US team, he never pitched in his inaugural season. Here is likely where the problems began.
Because while Sleeth was scouted as a talented prospect with a mid 90's fastball and excellent off-speed pitches, by the time the Tigers selected him his velocity had dipped, and it didn't recover in 2004. While his numbers were acceptable while in Lakeland, he certainly wasn't overwhelming (like he should have been given the competition), and he was hit hard in Erie. While there is no way to prove it, and the Tigers would never admit it, there's a good possibility that Sleeth's elbow problems began even before the Tigers drafted him.
This certainly isn't entirely the fault of the organization – pitchers often struggle distinguishing soreness with real injury, and given the competitive nature of athletics in general, the pitcher is apt to fight through the pain, even though it could have consequences down the road.
And those consequences, we are now seeing with Sleeth. His velocity still hasn't recovered to where it was when he was scouted as a top prospect, and his control has been all over the board, highlighted by his six walk performance this past weekend.
Control is often the last thing for a pitcher to regain coming out after Tommy John surgery, but 15 months removed from the surgery, Sleeth has three times as many walks as strikeouts in Lakeland (competition that he should still be blowing away based on pure "stuff"), and his ERA now sits at 10.80.
Injuries happen to everyone, and no matter how careful teams are with prized pitching prospects, injuries can still occur. On the other hand, the Tigers invested significant dollars (as well as an incredibly high draft pick) in Sleeth, a pitcher that may have been damaged goods before they even snagged him. And while it's still possible that Sleeth can turn it around and become a productive pitcher at the major league level, being realistic, the Tigers have likely reached a point where they're no longer expecting him to do so, and if he does, it's a bonus (much like how they never could have predicted Joel Zumaya would become the pitcher he has).
Andrew Miller on the other hand, the Tigers expect to do something. And not just any thing, big things. While it's unrealistic to expect the success that Justin Verlander has had so early in his career, Miller has the same skillset and potential to be a top of the rotation starter. He'll pitch in the ‘pen this season, but will be used sparingly, and the Tigers will shut him down at any sight of trouble.
But let the story of Sleeth be a lesson learned. As talented as Miller may be, there's no such thing as a sure thing. And it might be that way even before the Tigers know anything about it.