The team made the announcement during Sunday’s game against the Miami Heat. The Celtics had lost six in a row heading into the nationally televised game despite back-to-back triple doubles by the point guard who had been elected to start for the East in the Feb. 17 All-Star game in Houston.
Rondo reported to the TD Garden on Sunday for a pregame shootaround but was taken to a hospital after complaining of knee pain. The initial report was a hyperextended knee, but tests showed the ACL tear.
The injury usually takes up to a year for recovery. Surgery had not been scheduled as of Sunday afternoon, team spokesman Brian Olive said.
Rondo was averaging 13.7 points and 11.1 assists this season while the Celtics struggled to remain at .500. They entered the day with a 20-23 record, holding the eighth and final spot in the Eastern Conference playoff race.