Major League Baseball(BALTIMORE) -- Baltimore Orioles pitcher Jason Hammel will have arthroscopic surgery on his right knee Monday, and is expected to miss at least a month on the field.

“Obviously, it is not what I want to do, but it is what needs to be done," Hammel said. "I can’t keep pitching on a bad leg and start doing things with my arm and hurting things there."

Hammel has been having knee pain for a couple months. It finally became too much during last Friday's game versus Detroit, and he was pulled in the fourth inning.

Hammel is having a career season. The 6-foot-6 right-hander has eight wins, 106 strikeouts and 3.54 ERA in his first season with Baltimore.

Hammel has been placed on the 15-day disabled list. Pitcher Steve Johnson was called up from Norfolk to take his place.

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