Assuming they keep Gonzalez and whomever they draft at #32 the Celtics will have 14 players under contract after the draft. They'll have Horford, Craig and Kornet as free agents. My best guess is they re-sign Horford and Kornet, let Craig go, draft a center at #32 (Kalkbrenner or Raynaud) and then dump Niang somewhere for the salary savings.
Guards: White, Simons, Pritchard, Davidson
Wings: Brown, Hauser, Scheierman, Walsh, Gonzalez, Tatum(inj)
Bigs: Horford, Kornet, Queta, Tillman, #32Draftee
They'd go into next year with the option of maybe spinning off either Simons or Hauser for additional savings to MAYBE get completely under the tax before the trade deadline depending on how things look.