We have, arguably, the most depth of any big man rotation in the NBA.
Horford-Baynes-Morris-Theis-Williams-Yabu
I think Bobby Portis would be after Williams in that rotation. How does that help our depth? I'd rather keep Yabu. He seems like a good lockerroom guy that brings energy to the court and can stretch the floor from the top of the break.
Last season, Baynes averaged 6 pts and 5.5 rebs (this season he is down from that). Portis averaged 13 pts and 7 rebs (this season, Portis has only played 5 games but is around 10/10). I understand that Portis has had locker room issues but he is 23 (Baynes is 32). I don't get to see Portis play much but in the instances that I have, he has been good, solid.
I think Portis would be much better than Baynes playing next to Horford or Morris. I don't see this as a huge upgrade, just reinforcing a soft spot. Horford is clearly ahead of Portis as is Morris but I don't see Morris as a true big. Apparently, people are much higher on Baynes, Theis, and Williams than me. I like the future of Williams just fine, but I like the present of Portis much better.
Direct comparisons of stats are unhelpful. 13/7 on a team that went 27-55 is not good. Someone has to get points. Someone has to get rebounds. But that does not mean he is contributing to winning basketball.
He can't even get starts over Robin Lopez, Wendell Carter, Jabari Parker, Lauri Markannen, or Nikola Mirotic. I actually like Bobby Portis' game in the limited time I've watched him, but there must be a reason he can't get starts on a terrible basketball team.
Alot of being a big man in the NBA is great positional team defense, especially on the pick-and-roll, but whenever I've seen Portis against the Celtics, the Cs guards have torched Portis in the pick-and-roll time and again. That doesn't happen against the Cs bigs. If he puts up some points and gets some rebounds, but can't contain penetration, he can't play in the playoffs (Greg Monroe).
Again, I like his athleticism. I like his length. I like his competitiveness. I like his shooting. I like his potential. But I don't like it enough to take minutes away from Williams, who I consider to have much more potential, or to take minutes away from Theis, Morris, Horford, or Baynes, who are much better team basketball players.
Plus, I'm unreasonably high on Yabusele. I tend to think he is going to have a long career in the NBA. I think Yabu and Portis are at the same level. I wouldn't give up a pick plus Yabu to get a comparable player. I definitely wouldn't give up a starting guard (Rozier) and Yabu for a comparable player and a guy who won't be in the NBA when his rookie contract runs out.