Outside Box:
Put Rob Williams on Kevin Durant. Durant kills us one on one. Give Rob a go. It might cause problems with Durant on his jump shot, which is impossible to block. At least Rob could make him feel his presence.
That's all I got.
That's what I would do also. He's clearly giving Durant and Harden issues on the perimeter. but he must avoid foul trouble.
Covering Griffin and his 6PPG is a waste of Rob's talent. There are other players on the roster that can cover Griffin and could switch onto Durant and leave Williams with the screener.
Otherwise, play a box and 1 with Harris as the target. He's shooting over 56% beyond the arc, while the rest of team is shooting 29%,