Sounds like conjecture that got misinterpreted as a rumor to me. Logically it makes some sense, but I doubt there's any basis to it.
It's crazy what it takes to come up with a rumor these days. An author gives an opinion on twitter, but states it as fact. Then, a different author gives his opinion talking about an imagined asking price for the Celtics. Last, a third author takes those two statements together, and comes up with a story about the rumors.