He was fine in spots so far. +2.8 in the playoffs, that's pretty much what you're going to get out of a back-up 10 minute a night center.
This is why Anderson and Tucker will play backup 5 and Clint has to be at peak energy every minute he's on the floor. They have to make Draymond commit to them, and Nene can't do that, and Green is not going to get as tired as KAT/Gobert did chasing Capela.