So Celtics will now need to shed some salary to get back under the tax, right?
By my calculation, yes. Assuming they sign their first round pick, they would be over as things stand now by about $2.3M or so depending on what they sign Cenac for. But Banton is not guaranteed as I understand it. They could easily cut him and reduce by $2.8M. They have until January, I believe.
They have 15 players with Banton? So cutting him would put them at 14? Or is it a different number?
If you look at a site like Spotrac, they have 14 with Banton but excluding Cenac, who has a slot value a little less than $200k more what Banton makes. If you dump Banton and add Cenac, they are about $800k over the tax with 14 players. Derrick White has about $2 million in incentives, most of which are playing time dependent in some way (I believe one incentive is straight games played, and the another is making all-defense, which requires him to play 65 games). So if White, god forbid, should suffer a moderate injury that costs him a month or so, the Celtics are likely under the tax with no other moves needed. If not (a good thing) they could move a player at the deadline who is out of the rotation and sign someone else at the minimum. They may do this anyway.
Anyway, doing nothing else they are at 14 on the roster, and will likely swap Cenac for Banton, staying at 14. Getting under the tax will be easy at the deadline if it does not happen naturally.