He was almost always off on the weak side, keeping a help defender away from the rim, while the scoring guards (Hepburn, Edwards) present a dual threat on the other side. He's being used as an offensive facilitator.
Louisville didn't really crash the offensive boards either, which is an area Noah is good at. Again and again last night he'd be watching rebounds from the corner as he turned to recover on defense. The way the Cardinals use him doesn't keep him around the rim as much as it - IMO - should.
Point: Not surprised that his #s are down given how he's being used. In Pope's system he had more freedom, and was around the bucket more, and was a more featured 3 point shooter.