Both Fish and Melo said the soreness in the knee is a result of the ankle injury and favoring that leg. He was literally unstoppable before the ref injury, it's no coincidence that he hurt his ankle and played extended minutes on it before the soreness set in. 31 playing the best ball of his career, period...he wasn't playing regressed ball, as soon as his legs were back he was scoring efficiently while passing and rebounding at rates that matched his career high. When he regresses, talk age, but until then, that's a speculative argument only.
Neither of them can guard C's all game. Melo operates from mid to long range which allows KP to be both a stretch AND interior presence because KP is better playing inside the three point line right now. Blake's passing might compliment KP, but Melo's passing was already doing that.