CINCINNATI - Austin Kearns needs surgery to remove scar tissue from his aching right thumb, sidelining the Cincinnati Reds outfielder for another four to six weeks.

Kearns developed a sore spot on the inside of the thumb last month, eventually forcing him onto the 15-day disabled list for the second time this season. The soreness hasn't gone away, and doctors decided Tuesday that surgery is the only option left.

''I'm glad it's a situation where it's not something that's going to end my season,'' Kearns said, following a 7-5 loss to the Mets. ''Hopefully I'll be back by the end of July. After all that we tried, this obviously needed to be done.

''I knew (surgery) was a possibility. It was definitely a last resort.''

Dr. Timothy Kremchek said a bone spur, scar tissue and a callus will be removed Friday morning.

Kearns tried to take batting practice Tuesday with a padded glove imported from Indonesia, but the thumb hurt the first time he hit a ball.

''It didn't work,'' Kremchek said. ''Today after the first couple of hits, it turned red. That's a sign it wasn't going to work.''

Kearns, 24, tore a ligament in the thumb in 2001 and missed most of a season in the minors. Kremchek said the ligament is fine, but scar tissue from that injury is causing problems now.

The Reds tried treatment and pads to get the pain to subside, but it never went away.

''I know he's frustrated,'' manager Dave Miley said. ''He has basically tried everything you could try to rectify or play through it. He tried everything under the sun, except what he's going to have done.''

Kearns emerged as one of the NL's top hitters in the opening months of last season, before tearing his right shoulder in a home plate collision on May 21. Kearns got hurt again on April 26 when Ryan Vogelsong's pitch broke a bone in his forearm, just above the wrist.

The thumb started to bother him when he returned, and he didn't play after June 1.