Maholm underwent an MRI that revealed the tear. The Dodgers said treatment plans are still to be determined, but the injury almost certainly will require reconstructive surgery. Maholm tore the ACL in his left knee in high school.
"Unfortunate for us. Unfortunate for him ... It's just unfortunate to lose a guy like that at this time in the season," said manager Don Mattingly."
Maholm's loss is a double blow because he is a swingman who was an option to step into the rotation with the recent struggles of Dan Haren and Josh Beckett.
"It changes some roles around," said Mattingly. "Obviously, we used Paul as a guy who could be a spot starter, use him for length, kind of the long guy in your bullpen. Depending on where you're at, you can use him short. Now, we have Paco, who's more of a situational lefty for us. We'll have to try to figure out that long man. It definitely takes away from our depth a little bit with starting pitching. It leaves us with some gaps."
Maholm was injured as he covered first base in the seventh inning of Friday night's 8-2 loss to the Cubs. He was 1-5 with a 4.84 ERA in eight starts and 22 relief appearances.
Ken Gurnick is a reporter.com. This story was not subject to the approval of Major League Baseball or its clubs.