BOSTON - Ryan Howard has promised this much: If his left knee hurts, he will tell his bosses. And while the pain may prevent him from playing on some days, he wants to avoid the disabled list.

Howard said his knee hurt Monday. But he decided he could play after sitting Sunday. So Charlie Manuel inserted him into the Phillies lineup.

"You play hurt, you play injured to the best of your ability," Howard said. "Guys go out and play hurt, play injured. That's the part of your competitive nature. But it's about being smart about it, too. If it's something that continually bothers me to where it's 'I can't go right now,' I'll let them know."

Both player and team are faced with a difficult situation. A lineup already missing Chase Utley and Carlos Ruiz cannot afford the loss of Howard. But if Howard's numbers continue to suffer while playing hurt, the decision could be forced.

The Phillies are betting on Howard being a productive player through at least age 36. The second season of his five-year, $125 million contract is characterized by a left knee injury that could linger for months.

Howard has inflammation in his left knee that was eased by a cortisone shot May 19. That injection, apparently, helped for a few days. The team was vague in diagnosing Howard, saying that various tests were inconclusive as to whether Howard had torn his meniscus. But head athletic trainer Scott Sheridan admitted it was possible.

Players can play through a torn meniscus. Cincinnati first baseman Joey Votto attempted that for two weeks last July before opting for arthroscopic surgery. Votto originally was expected to miss four weeks. He was absent for 52 days.

Howard said he was not ready to consider surgery and did not want the injury to serve as an excuse for his poor play. He did say "it plays a factor with it being my push-off leg."

Howard's .719 OPS ranked 113th out of 168 qualified hitters entering play Monday. His $20 million salary in 2013 is 10th highest among position players.

Manuel said it might be easier to sit Howard if Utley and Ruiz were available. The manager was confident in Howard's ability, though.

"I'm convinced," Manuel said. "I think he's going to break out of it and I think he has to keep grinding it out and stay with it. Do the best he possibly can. We have to stay with him because like I've always said, he is a guy that knocks in all the big runs for us."

Can he do it even on one leg?

"His leg is going to always be bothering him," Manuel said.

Manuel had the option of using Howard as designated hitter Monday in American League play. But Delmon Young's defensive inadequacies made him the DH. Howard and his injured knee were at first base.

"Right now I'm looking at it day to day," Howard said, "and trying to run with the good days."

Extra bases

Jonathan Papelbon, Boston's closer for six seasons, returned to Fenway for the first time. "Hopefully, I'll be received well, but I will also accept the fact that I might not," Papelbon said. The Boston fans applauded when a video tribute was shown before the second inning. . . . Cole Hamels lost his eighth game Sunday. Since 1970, only two other Phillies pitchers lost eight games before the month of June: Don Carman in 1989 and Jim Bunning in 1971.