I had waded into this discussion in the Celtics Sell thread. I don't think they are going to do anything involving a starter this off season. Hopefully this is not just be wishful thinking. In broad terms, Tatum goes up about $20M, Hauser goes up $8M, Kornet is a UFA at $2M and will go up, and we have to do something with Horford who is at about $10M now. I am thinking they just accept Tatum's increase, they hope to get Horford down some, Kornet is going to get a raise, and then maybe they trade Hauser to save money. The 2nd apron threshold is projected to go up from about $189M to about $208M so that provides some headroom. I am not sure that the tax threshold is going up based on what I am able to find. Someone may be able to confirm this.
Even though Hauser is a better overall player than Kornet, Kornet may be more important to the team. We know that Porzingis and Horford will miss time. Plus transactionally, if we don't sign Kornet, we get nothing in return. We can trade Hauser. Maybe if you think Queta can step up, you live with losing Kornet, but I am not there. If it was me, I would trade Hauser to pay Kornet and Horford. Now if the Celtics decide to just pay everyone (reduce Horford, increase Kornet), great, but I suspect they will have to do something this off season. And Hauser may return decent value, maybe a young big that can project to replace Horford as the first big off the bench. Then you live with Craig and Scheierman taking Hauser's minutes or something like that.
In the 2026 off season, they will have to do something with Porzingis and by that time, it is very likely they will need to replace Horford with a rotation caliber big. Porzingis only plays 60-65 games per season, at best, that is pretty well established. And there is always the looming risk of a serious injury, so we may not need to bump him up all that much. But it is going to cost to replace Horford unless we get really lucky in the draft or something. A lot can happen between now and the 2026-27 off season so it is hard to project. Even this offseason is a ways away. But we all just can't help ourselves from over analyzing this.