Rondo sat out practice on Thursday one day after suffering the injury in a win over the Toronto Raptors. The point guard landed awkwardly on his hand during a fall after being fouled while going to the rim. Rondo shot his two free throws but sat out the rest of the game after that.
Celtics coach Doc Rivers announced Thursday that Rondo was to have an MRI on the wrist on Thursday night, putting it off for a bit so that he could watch practice during the day.
"He's doing all right," Rivers told reporters. "I doubt if he plays [Friday], but we'll see."
If Rondo can't go Friday night, it will likely be second-year point guard Avery Bradley getting the start instead.