updated 5:42 p.m. ET March 4, 2006

PEORIA, Ariz. - The Chicago Cubs insist pitcher Kerry Wood is not risking more damage to his right knee by throwing off the mound on Monday — one day before he is scheduled to undergo arthroscopic surgery.

“His doctor said it would be better if he continued to throw until the surgery to keep his arm strength going,” manager Dusty Baker said Saturday.

Wood was expected to miss the start of the season after undergoing surgery on his right shoulder on Aug. 31. Trainer Mark O’Neal said Wood began experiencing “a tapping palpable pain” on the upper bone of his thigh about a week ago and an MRI revealed a medial meniscus tear.

O’Neal and Baker said the knee flares up when Wood is running — not pitching. And Dr. Lewis Yokum, the surgeon performing the operation in Los Angeles, gave the OK to keep throwing.

Although O’Neal called it a “one or two-week setback,” the latest injury only added to Cubs fans’ angst. The 1998 NL Rookie of the Year and an All-Star in 2003, Wood has been on the disabled list nine times in a professional career that began in 1995.

The 28-year-old right-hander missed the entire 1999 season with an elbow injury and went to the disabled list three times last season. He was 3-4 with a 4.23 ERA in 21 games last year and had been limited to the bullpen before shutting it down last year.

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O’Neal said Wood will return to Arizona on Tuesday afternoon and immediately resume workouts.

“The key for us is to try to do whatever we can to not lose any arm strength,” O’Neal said. “I’m not sure he’ll be able to throw for a couple days. But we can ... put him through different dynamic workouts. And we’ll get him outside throwing as soon as we can.”

Pitching coach Larry Rothschild said, “We’re going to make sure he exercises the arm without straining the knee.”

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While Wood heads to surgery, Mark Prior continues to build his strength after being slowed by a throat infection that sent him to the emergency room during the winter.

Rothschild said Prior will probably throw about 50 pitches on Sunday, followed by a light session on Monday and a bullpen throwing session on Tuesday. He may face hitters on Thursday, but the Cubs aren’t sure when Prior will appear in a preseason game.

“He keeps progressing,” Baker said. “That’s what we want.”

Rothschild wants Prior to start three or four preseason games. But injuries have limited the right-hander to one Cactus League appearance the past two years and caused him to start the 2004 and 2005 seasons on the disabled list. After returning from elbow soreness last year, Prior went back to the DL after taking a line drive to the elbow. He finished 11-6 in 27 starts with a 3.67 ERA.

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