Skill seems to be eroding? Did you forget he's only 26 years old and has only been in the league for 5 years? Why would he be getter worse? Everyone has a bad year or two, but when they haven't even reached their prime, their skills are not "eroding" as you put it.
He will be improved and much better this year. He will get back to the old D-Train soon enough, and I'm happy for him to do it on the Tigers. 
Dontrelle Willis goes 16-8 3.75 ERA
Justin Verlander goes 20-11 3.54 ERA
Jeremy Bonderman goes 15-10 4.10 ERA
Kenny Rogers goes 8-4 4.03 ERA
Nate Robertson goes 16-11 3.75 ERA
Todd Jones goes 4-4 4.10 ERA 29 saves
Fernando Rodney goes 5-3 4.02 ERA 10 saves
Jason Grilli goes 6-2 4.50 ERA 6 saves
Joel Zumaya goes 3-3 2.80 ERA 15 saves
Denny Bautista goes 5-3 3.80 ERA
Francisco Cruceta goes 3-2 4.00 ERA
101Wins 61 Losses for 2008
Post Season Predictions to follow....
aight fellas, im from michigan and what weve seen the last 2 yrs wont be what we see this year. d-train will have the catcher he had when he was a rookie, chuck hernandez (Tigers pitchin coach) will help him out alot, and the fans in michigan already love him which will help him out big time.
D-TRAIN= 15-8 4.05era
tigers offense will help him out too