He definitely misses the trip to Fulham on Saturday and is only likely to feature again this season because of the current injury crisis.
"Rehabilitation will take four to six weeks," explained Sir Bobby.
"But, and it is a but, the surgeon is saying he could possibly play as long as he does not damage it again or falls badly.
"So it is a risk but it is a risk that we might have to take and JJ is quite happy to take that risk.
"At the moment it is too painful and too sore. He will be better tomorrow but will not be playing on Saturday.
"Whether we push him in on for Monday (against Aston Villa) depends what happens with injuries and how we get on this Saturday.
"Whether we use him over the next two to three weeks also depends on how he recovers and whether he is comfortable with it.
"At the moment, he can't even run. He has had a very nasty operation."