Dionte Christmas and Jabar Smith.
It's Jamar Smith, but yeah, those two guy seem like realistic targets.
The trouble is that the Celtics only have two open roster spots, which seems weird considering they only really have NINE rotation players at the moment. I think Barbosa will need to be waived, unless he gets sent out in some minor trade for salary matching purposes.
The Celtics really need another guard, a 2/3 type, and a 4/5 type.
My ideal would be getting Dejaun Blair for very little (e.g. Barbosa, cash consideration, and a couple of future second rounders), then signing Dionte Christmas and maybe somebody like Andy Rautins (3 pt shooter) or Rashad McCants. Or maybe you just get another small guy like Jamar Smith.