By Gary Washburn, Globe Staff

The Celtics' fears that Leandro Barbosa's knee injury was serious came to fruition as an NBA source said he will miss the rest of the season with a torn left anterior cruciate ligament, the same injury sustained by Rajon Rondo.

Barbosa was hurt, like Rondo, in non-contact fashion, twisting the knee awkwardly as he drove to the basket late in the third quarter of the Celtics' 94-91 loss to the Charlotte Bobcats. Barbosa immediately passed the ball to Jeff Green and then crumbled to the floor near the photographer's area.

He was carried off the floor by head trainer Ed Lacerte and rookie center Fab Melo without placing any pressure on any leg. He was able to walk out of the arena under his own power but a post-game examination indicated that it was a ligament tear.

A magnetic resonance imaging revealed the tear, meaning the Celtics have lost a third player to season-ending injury in the past 16 days. Rondo was felled with a torn right ACL while rookie Jared Sullinger underwent back surgery.

As for Barbosa, it is uncertain whether he's played his final game as a Celtic. He signed a one-year deal and is a free agent this summer. He averaged 9 points and 2.6 assists in his previous five games.

The Celtics will now be in search of a point guard but it's likely not going to be Delonte West. An NBA source said the Celtics have not reached out to the troubled former Celtic about a return. Also, former Washington Wizards draft pick Shelvin Mack was in Rio Grande Valley with NBADL Maine and was expected to play.

He has been mentioned as a possible replacement.