IMO, he was only 'noticeably slower' after he ripped up his groin and came back too soon, after missing only one game. He should have rehabbed longer, rather than trying to run on one leg--much like Nick O'Leary shouldn't have run the 40 at the combine when he wasn't fully healed and ran a poor time.
A healthy Fred is the perfect change of pace back to Shady--and I expect him to make a nice impact once again this year.....