Did he play that badly? Not from my perspective.
He was hesitant when he was open, but two steps from the basket. He made a pass QG didn't catch, how is that his fault 100%? He could have gone to the basket, but split second decisions, with minimal real court time, what do you expect? May be JB said to him beforehand "whatever you do, don't shoot, your job is to rebound and defend". JB clapped in encouragement on the sideline, so that says something.
He made a steal on the next play.
He didn't go up strong and foul on the go ahead play, again may be JB said to him "we are up one on the road, whatever you do don't foul!!!"
May be he was following instructions and did what he was told?
JB didn't do the "If I had anyone I wouldn't have put him out there" line he did with Roberson.
It is what it is. Hindsight is always 20/20.