Kerry Wood @ MindSay

Cubs pitcher Kerry Wood will be out at least four weeks after an exam revealed a partial tear in his right rotator cuff.

Wood underwent an arthrogram at Northwest Memorial Hospital Friday. The team said Saturday the options are conservative treatment or possible arthroscopic surgery on Wood's shoulder. A final decision has not been made yet on treatment.

Wood had undergone an MRI on June 26 in Cincinnati, but that did not include an arthrogram, which is more detailed and provides more information, the Cubs said.

Wood, 29, underwent arthroscopic surgery on his right shoulder last Aug. 31.

Wood began the season on the disabled list. After being activated, he went 1-2 with a 4.12 ERA in four starts before going back on the injured list June 7. He was on the DL three times last season, the final time on Aug. 30, one day before his surgery.

Wood had a huge year as a rookie in 1998 as he had a 20-strikeout game in his fifth major league start and won the National League Rookie of the Year Award.

Kerry Wood, coming back from arthroscopic shoulder surgery, most likely will make his first start of the season Thursday when the Chicago Cubs play the Washington Nationals.

Wood allowed a run on five hits and struck out three in five innings Friday in a rehab start for Triple-A Iowa.

"I had a couple outings where I had real good stuff," said Wood, who also threw five scoreless innings in a rehab start with Class A Peoria last Sunday. "Last night, I didn't have my best stuff, but I was able to make good pitches and not make a lot of mistakes. I felt good this morning. It's a good sign."

Chicago Cubs pitcher Kerry Wood will have minor arthroscopic surgery on his right knee next week, general manager Jim Hendry said Friday.

Wood's surgery will take place Tuesday in Los Angeles.

The 28-year-old Wood had arthroscopic surgery on his right shoulder Aug. 31 and was not expected to be ready for the start of this season. He's thrown off the mound a couple of times in spring training, testing his shoulder.

An All-Star in 2003, Wood was 3-4 with a 4.23 ERA in 21 games last year. He was slowed by injuries all season, missing about three months while going on the disabled list three times.

Cubs right-hander Mark Prior could be pitching off a mound by the end of the week, and rehabbing right-handers Kerry Wood and Wade Miller threw well Wednesday in their comebacks from shoulder problems.

Prior has had elbow problems during the past two spring trainings.

"I think we're going to a pretty extensive throwing program Friday and see how he reacts on Saturday, and go from there," pitching coach Larry Rothschild said. "There's a good chance he'll get on the mound Sunday, but if he feels real good, we might venture that on Friday. But we'll see."

Miller and Wood each played catch Wednesday, throwing about 120 feet.

"It's been impressive to where they are up to now," Rothschild said. "They're throwing the ball with pretty good force behind it. It's not so much what they can do today, but can they feel like they can do it again tomorrow? That's the basis we pretty much use to go forward."

Chicago is optimistic Prior can start in one of the first exhibition games in early March. The Cubs hope Wood can be ready to pitch in big league games in April and that Miller can be available in May.

Rothschild said Wood would take Thursday off and resume throwing Friday and that Miller would throw again Thursday.

Wood was on the disabled list from May 3 to June 28 last year because of shoulder problems and again from July 21 to Aug. 5. He ended the season in the bullpen, but the club plans on having him start this year.

Miller's season with Boston last year was cut short by shoulder pain.