I don't think Diarra plays great, but don't think he's as bad as you guys make him out to be. His makes plays with his athleticism and is at least as good defensively as Vogt.
Diarra was +2 in the most recent time he was in. He had a nice offensive rebound and a nice clearout to open the McNeal drive.
Did you not see him just slam the ball against the floor when he was trying to rebound it, he is not good at all