SAN DIEGO -- Tired of being reduced to a part-time player, Tony Gwynn will undergo arthroscopic surgery on his troublesome left knee Tuesday.

The San Diego Padres batting star hopes that doctors will have to clean out only the joint, which has little cartilage left in it due to five previous surgeries. In a best-case scenario, the 40-year-old Gwynn figures he would miss at least 4 to 6 weeks.

	Gwynn

If doctors find more serious damage or decide to perform a procedure to get new cartilage to grow, there's a chance Gwynn could miss the rest of the season.

Dr. Jan Fronek, who will perform the surgery along with Dr. Steven Copp at Green Hospital Scripps Clinic in La Jolla, Calif., said he couldn't say specifically how much time Gwynn will miss until after the surgery.

"We all know it's bone-on-bone, so I hope that maybe there are just some bits and pieces of cartilage that they'll need to get out, that might be caught in a joint," Gwynn said from his home Monday evening.

Gwynn has been bothered by inflammation in the knee off and on this season, and has had to have it drained seven times since spring training. When he was on the disabled list earlier this season he had injections of a substance that stimulates bodily fluid that lubricates the joint.

"I do feel that this is the best thing to do," Gwynn said. "I've done everything else they've asked me do. I took the injections, I played every other day, I've iced it for 15-16 hours a day. I've got to do what I want to do, and I want to continue to play. I don't want to be a part-time guy, I want to be a full-time guy. To me, this is my best option. I hate to sit on the bench."

Gwynn didn't start the last eight games but did make two pinch-hitting appearances. On Friday night at Cincinnati, he doubled to start the winning rally in the 10th inning, hobbling into second base. He was placed on the 15-day disabled list Monday.

The eight-time NL batting champion, who has 3,108 hits in his 19-year career, was hitting .323 with 12 doubles, one homer and 17 RBI.

The degenerative knee forced Gwynn onto the DL from April 29, when he was hitting an unfathomable .186, until May 16. A lifetime .339 hitter, he got his average back above .300 on June 7, the final game of a six-game trip against AL teams in which he was used as the designated hitter.

Fronek said Gwynn has definite cartilage damage. "We've known that, unfortunately, for a long period of time. In spite of all the measures we've taken, in terms of trying to deal with this non-surgically, obviously he's had more trouble and pain and swelling."

Fronek said the surgery may involve smoothing areas where the cartilage is rough or irregular. He added that procedures to get new cartilage to grow are difficult because the new cartilage is not as good as the original.

Also Monday, the Padres put right-handed starter Stan Spencer on the disabled list with a strained right elbow, which is expected to keep him out for 4-6 weeks. He is the fourth starter to go on the DL, and the ninth pitcher currently disabled.

Spencer was 2-2 with a 3.26 ERA in eight starts following his promotion from Triple-A Las Vegas on May 12.

In other moves, the Padres transferred backup shortstop Chris Gomez to the 60-day disabled list, recalled right-hander Will Cunnane from Triple-A Las Vegas and purchased the contract of outfielder Dusty Allen, who's making his first trip to the big leagues.

Gomez underwent season-ending surgery on his left knee on Monday. No details of that surgery, performed in Vail, Colo., by Dr. Richard Steadman, were immediately available.

Cunnane is up with the Padres for the third time this year, and is scheduled to start Tuesday night at Los Angeles. He is 1-1 with a 6.28 ERA in 13 big league appearances this year, including one start. At Las Vegas, he was 5-0 with a 3.19 ERA in eight starts.

Allen takes Gwynn's place on the roster, although Eric Owens has been starting in right field.