Yabu needs to lose about 20 lbs. He's a big guy with a paunch--much like Sullinger. He would be quicker if he was lighter. He's a big body under the basket, but he isn't solid like Baynes.
The guy I like is Theis. He looks in great shape, has a lot of extension, and knows where to go on the court. He can play inside or outside. Rebounds offensively very well, and plays good defense. I think he's surprised Stevens, and he might just wind up in the rotation.
They probably had guys like Yabu slated for the rotation, but Theis has shown more so far. He and Tatum have been the surprises, and should be in the rotation. Tatum could be ROY on a team where he could start.