"Actually, I told our TV and radio he was good because he was," Rivers said. "Then, he came in literally as I was walking out and said he can't go. So, that's a tough one, because we hadn't prepared for that one."
Nate Robinson will start in Rondo's place for the fourth time this season. Marquis Daniels will take on backup duties, and Avery Bradley will likely see the floor.
"It could be an interesting point guard rotation tonight," Rivers said.
Rondo missed three games from Nov. 21 to Nov. 24 with a strained left hamstring. His knee buckled in the third quarter of Friday's win over the Bulls, but he re-entered and finished off a 19-assist night. Rivers said he might consider sitting Rondo for a stretch of games again if need be.
"We may," Rivers said. "We get a two-day break after this and that's one of the things that went into this [decision]. Listen, it is what it is and we're just going to try to get through it."