john sickels of the sb nation runs a site at www.minorleagueball.com  He has some great insite that he brings everyday, much likejeff will do here, i am sure.

at any rate, john writes the baseball prospect book, and has shared his view of the tigers system.  i copied and pasted it here below.

Detroit Tigers Top 20 Prospects
By John Sickels
Posted on Thu Mar 03, 2005 at 11:21:20 AM CST

1. Justin Verlander, RHP, B+        
2. Curtis Granderson, OF, B        
3. Tony Giarratano, SS, B          
4. Kyle Sleeth, RHP, B-              
5. Joel Zumaya, RHP, B-              
6. Jeff Frazier, OF, C+            
7. Ryan Raburn, 2B, C+              
8. Chris Shelton, 1B, C+            
9. Juan Tejeda, 1B, C+              
10. Lucas French, LHP, C+            
11. Eric Beattie, RHP, C+            
12. Andrew Kown, RHP, C+              
13. Humberto Sanchez, RHP, C        
14. Brent Clevlen, OF, C            
15. Eulogio de la Cruz, RHP, C      
16. Collin Mahoney, RHP, C          
17. Josh Kauten, RHP, C              
18. Kenny Baugh, RHP, C              
19. Matt Vasquez, RHP, C            
20. Dallas Trahern, RHP, C          

Oh, boy, what a dismal system. Even Verlander at Grade B+ is a risk; he has no pro track record, and while he has an excellent arm, there are some questions about his command and his polish. I really like Curtis Granderson, one of my favorite Grade Bs and perhaps should be a B+. I don't know what people are talking about when they complain that he's not toolsy enough. He runs well, has a quick bat, and I think is underrated as an athlete. He's also very intelligent. Giarratano is an infield version of Granderson: a polished guy who is an underrated athlete.
After that, things really thin out fast. Sleeth and Zumaya are hard throwers, but both have problems with their command and mechanics. Jeff Frazier looks like a possible sleeper, but he's an '04 draft and we need to get more data about him. Shelton and Tejeda can hit, but are limited defensively and will have to fight for platoon/DH/1B roles.

The Tigers have a bunch of live arms, with several guys who can hit 95 MPH or higher. But strangely enough most of them don't actually pitch very well. De la Cruz and Sanchez both burn the radar, but both have sketchy track records and are more throwers than pitchers. The same thing can be said for Collin Mahoney and Josh Kauten. De la Cruz's K/IP is bizarrely low for a guy with an alleged 100 MPH fastball.

On the other hand, guys like Kenny Baugh and Matt Vasquez throw strikes and know how to pitch, but have marginal stuff and will have to be perfect to survive at higher levels. A sleeper is Dallas Trahern, a 34th round pick from an Oklahoma high school last June, but he is a long way away. I haven't given up on Grade C outfielder Brent Clevlen, but he needs to rebound this year.

Other Grade C guys you could include are RHPs Nate Bumstead, Josh Rainwater, and Jay Sborz, and OF David Espinosa.