The Philadelphia Phillies' slugger needs surgery to repair a torn meniscus in his left knee and will miss at least six to eight weeks. An MRI on Monday confirmed the tear in his knee. A date for surgery hasn't been set.
"It could have been much more significant damage," general manager Ruben Amaro Jr. said. "We don't want any of our players on the DL. But we know what it is and it's treatable. Hopefully we can get him back in time to play this year."
Howard, the 2006 NL MVP, went on the disabled list Saturday. The three-time All-Star was hitting .266 with 11 homers and 43 RBIs. He was noticeably hobbling during games before he was shut down. He said he continued to play through the pain because he thought he could perform.
"We have to take care of it," Amaro said.
Howard played his first game last season on July 6 after tearing his left Achilles tendon making the final out in the 2011 NL division series. The 33-year-old first baseman has been on a steady decline since signing a $125 million, five-year contract extension on April 26, 2010.
Howard averaged 50 homers and 143 RBIs between 2006-09. He hasn't hit more than 33 or driven in more than 116 runs since then.
Darin Ruf, who hit 38 homers at Double-A Reading last year, replaces Howard. Ruf had been playing left field in Triple-A.
Howard is the latest star player to land on Philadelphia's disabled list. Chase Utley and Carlos Ruiz missed significant time and Roy Halladay remains out after having shoulder surgery.
Backup catcher Erik Kratz had surgery for a torn meniscus on June 12 and already has started a rehab assignment, so he's ahead of schedule.
"Hopefully we will have the same sort of time frame, but everyone's knee is different," Amaro said, comparing Howard to Kratz. "We can only speculate the length of how long it will take to get him to rehab. We'll shoot for the conservative one and hope he comes back faster."