More details on Spurs luxury tax situation:
Spurs are $556K below the tax.
Signing a player today to the min for the rest of the season would cost $276K against the tax.
So, even when factoring things like unlikely bonuses that could raise Spurs team salaries, Spurs can without a problem waive a player and sign someone else for the rest of the season.
To me, the key question is what Blair wants. There are two options:
1) Blair is fine with staying a Spurs for the rest of the season.
Is there an available player worth waiving Blair?
2) Blair wants to be bought out or waived.
Should Spurs keep an unhappy Blair or accepting his request?
In the case 1), I think the answer is no. I don't see a player significantly better than Blair available.
In the case 2), I would be for letting Blair go. Blair isn't good enough to risk hurting the chemistry and he deserves that "gift".