JJM's lost 20lbs during rehab...

[Canthony]

Like others have said, it's just easier on the knee. Less body weight is less stress on the knee. Once it gets strong enough to carry the normal load, I will guess he will be with the weight trainer every day. They referenced this is the movie "Draft Day" as well with Brian Drew rehabbing from his knee the year before.

[greediron]

I suspect he was following medical advice from sports medicine professionals.  I doubt he just decided to stop working out,  besides the largest muscle groups are lower body and since you arent going to work jist 1 leg,  its stands to reason that people that have to force themselves to eat to keep enough calories going to just maintain playing weight, would see much more dramatic loss in times of not training than the normal Joe.

Yeah, it isn't like a QB needs huge biceps either.  Below the waist is certainly a majority of muscle weight.