You could use the search engine to read some of the stuff that's been previously discussed.
The biggests concerns are his severe quad injury; which I've heard is fully healed, and the GB O-line; which I hear has not healed. Then there's always that fumble thing.
I think he will blow against DaBears today, but the next two weeks he has the Saints and Lions. If he has anything left he should be a good play against those two. I look for him to be a nice fill in RB when the match-up is right. He has a high up-side for the relatively low price demanded on draft day.
I think, therefore I am. I think fantasy, therefore I am unreal?