NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

Rajon Rondo has a torn ACL. Surgery date TBD.

— Boston Celtics (@celtics) January 27, 2013

Mystery of this injury is after #hawks game, Rondo talked with media, was not favoring or icing knee, like a normal postgame. #celtics

— gary washburn (@GwashNBAGlobe) January 27, 2013

From Celtics.com

Rondo Tears ACL, Surgery Date TBD | The Official Site of the BOSTON CELTICS

BOSTON - Rajon Rondo is expected to miss the rest of the season with a torn right ACL after hyperextending his right knee. Rondo was injured in Friday's loss to the Atlanta Hawks. He went through warm-ups on Sunday at TD Garden but was a late scratch from the game vs. Miami and instead underwent an MRI at New England Baptist Hospital. Courtney Lee started in his place at point guard. The Celtics have yet to determine a date for his surgery.