I think a lot of the answer here depends on how he is doing in the eyes of the Bills staff. Although he's been off the field for awhile, I'm sure he's been under the watchful eyes of the coaches as he rehabs. They are watching how he works out, takes mental reps, watches his conditioning, etc.
I do recall that Jauron called him out at last year's camp for dogging it, which concerned me at the time given the fact that it was his very FIRST training camp as a pro.