"We have to take care of it," Phillies general manager Ruben Amaro Jr. said. "He's going to have to have a procedure. It's just a matter of who does it and when."
Howard had a MRI exam Monday, which revealed the tear. The tear is new. He had a MRI exam in May, but that revealed only a fraying of the meniscus.
Amaro said the tear is similar to one found in Erik Kratz's left knee. The Phillies issued the same six-to-eight-week recovery period for Kratz following his June 12 surgery. He began a rehab assignment Monday with Triple-A Lehigh Valley and could rejoin the club before the end of the week, which would put him two weeks ahead of schedule.
"He moved pretty quickly," Amaro said of Kratz. "Hopefully we will have the same sort of time frame. But everyone's knee is different. 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."
Howard hit .266 with 11 home runs, 43 RBIs and .784 on-base-plus-slugging percentage in 317 plate appearances before the injury. His presence will be missed, but the Phillies are hoping rookie Darin Ruf will seize the opportunity.
Amaro said he expects Ruf to get the bulk of the playing time at first base while Howard is out.
Howard has a growing history of health problems with his left leg. Each of his four trips to the disabled list in his career have involved the left leg: strained left quadriceps in May 2007, sprained ligament in his left ankle in August 2010, torn left Achilles in October 2011 and now the torn meniscus in his left knee.
Howard also revealed Sunday he has a foot problem, although it is unclear how troublesome it is.
"He may have some discomfort there," Amaro said. "I don't know anything about his foot."
The Phillies are hopeful the leg injuries have played a significant role in Howard's decline offensively the past two seasons. Since the Achilles surgery, he has hit a combined .244 with 25 home runs, 99 RBIs and a .752 OPS in 609 plate appearances over 151 games. He also has been one of the least productive hitters in baseball against left-handed pitchers.
Asked if the knee injury could be related to the Achilles injury, Amaro said, "It could have. Really, I couldn't tell you that. It's possible. Everything is connected."
Amaro said the surgery will be scheduled after consulting with Howard's agent, who will help them decide which doctor to perform the surgery.
"I'm encouraged," Amaro said. "It could have been much more significant damage. 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."