i mean rest hasnt worked, whatever it is they gotta solve it somehow. i dont see him retiring just yet, hes way too young.There's really only one other option as you've mentioned in this thread and I'd be hesitant to do that since previous surgeries aren't fixing the issue.
If Chicago is going to blow it up at some point and his injury just isn't going to heal for him to play again, I'd try and nudge him into medically retirement so he still gets his money and the contract doesn't count towards the cap.