Rajon Rondo has a torn ACL and is out for the rest of the season.
Celtics Hub did a little digging and came up with a play with about 2:30 left in the second overtime where Rondo may have injured his knee. He went up on a jumper and came down a little awkwardly and his knee buckled.
Thing is, Rondo didn't leave the game and actually responded by knocking down a jumper with about a minute left. While again, apparently playing with a torn ACL.
There was another play late in the fourth where Rondo drove with about two minutes left and came down hard on his knee and limped away.
Which play was it? Unknown at this point, but what we do know is that Rondo tore it, and it's bad news.