The Boston Celtics expect to keep one of their four training camp invites, leaving one roster spot open to add a late buyout or remaining free agent.

“I don’t know [if the Celtics will carry 15 players], I would say most likely not,” said Rivers. “There are guys still out there, unsigned. And we might want to sign them.”

Pressed on potentially signing a veteran, Rivers cracked, “First come, first serve. Can we make an announcement to all the free agents?” He then laughed before turning more serious.

“Really, we’re looking around. I still think there will be buyouts, probably starting [Thursday]. So there’s so many things that could happen and we want to make sure if that happens, we’re able to [sign a free agent] quick instead of a delay. We may keep 15 for a couple more days, but after that, we’re probably going to go to 14.”

Based on preseason results and Boston’s roster needs, Greg Stiemsma will almost definitely make the Celtics, and Michael Sweetney, Jamal Sampson and Gilbert Brown (who Danny Ainge has strongly desired since before the lockout, but didn’t exhibit poise during his brief stints in the lineup) will be cut.

A roster spot will remain open, which the Celtics will (hopefully) use on either a shooting guard or center. Count DeShawn Stevenson out of the running, if he was ever in the running — the wing is reportedly close to inking a one-year deal with the New Jersey Nets, and could do so as early as today. Available names that the Celtics have reportedly discussed include Michael Redd, Joel Przybilla, James Posey and Al Thornton, none of whom are particularly appealing, whether due to age (Redd, Przybilla, Posey), injuries (Redd, Przybilla), or basketball insanity (Thornton).