Michael Turner is a player, but situation is king in the NFL. Granted Turner's highlights are impressive, but that was on a stacked SD team, after LT had worn them down. Turner benefitted a whole lot coming in behind the most complete RB ever to play the game. And you have to factor that in.
But if you look at Turner's NFL highlight video to the COLLEGE highlight videos of the draft class in 2008, he looks pretty damn good. Backing up LT is still not as much of a detractor when you like at NFL competition vs. college competition. You comare apples to oranges here and Turner starts to look better than a similar guy in Jonathon Stewart. There is a balance there of course, but how good Turner is going to be all comes down to how Atlanta is going to look in 2008 and beyond. And you also have to look at whether Norwood as a change of pace will keep Turner healthy and more productive or actually limiting to the extent of lost production.
Overall, I think Turner is a solid RB#2. He's comparable to other solid players in bad situations. There is upside there, but there is also downside.