I don't think D Sabonis is available right now but it may become available mid-season or next summer. Sacramento are due for another disappointing campaign. That might be the final straw for them. They may chose to rebuild and make D Sabonis available in a trade.
You make a good point that as we approach this upcoming trade deadline influential players make become available.
The Celtics will hopefully be big players here, with the focus not on the back 1/3rd of the 2025-26 season, but on the entire 2026-27 season.
As you say, if the Kings are putrid and want to get off of Sabonis' contract we could potentially add that crucial big-man piece for the 26-27 season a bit early.
With that perspective in mind, and the C's not worrying about the 25-26 season, we could be open to a lot more scenarios.
For example, let's say an impact player has an injury that requires season-ending surgery, but not something so significant that would keep them from being healthy at the beginning of the following season.
If someone like Simons is tearing it up for us, and a team needs an offensive sparkplug like him for a playoff push (let's say Dallas needs some firepower) it might open the C's up to (potentially injured) impactful players that right now are considered "off the table."
And while that sounds like I'm describing Anthony Davis, I'm not.