The answer appears to be that he’s not keeping the weight off.
According to Mike Garafolo of FOX Sports, Russell has gained back some of the 51 pounds he lost while training this offseason.
A sore knee has doubtless contributed to the weight gain, as swelling has kept him from working out the way he had before.
Russell has a big frame, and has always leaned toward looking soft. But if he can’t keep it off at a time when he’s working on a last chance, that chance may never come.