"I feel we got the best news we could possibly get," general manager Brian Cashman said. Through a spokesman, team physician Dr. Stuart Hershon said an MRI taken on Monday revealed "inflammation." Clemens will be in Houston tomorrow to be examined by Astros team physician Dr. Thomas Mehlhoff. It is expected he will receive a cortisone injection.

"We're going to deal with this aggressively, as fast as possible, so I can continue on," said the 45-year-old Clemens, who is 6-6 with a 4.45 ERA in 16 starts and one relief outing.

Clemens will miss his start on Sunday at Kansas City, with Mike Mussina likely to replace him. Clemens could return for the Red Sox series at Boston's Fenway Park Sept. 14-16.

"We're thinking one start. We'll see," manager Joe Torre said. "He'll have to go out and throw on the mound before he can pitch. ... His elbow seems stable. There doesn't seem to be any damage that concerns anybody."

Clemens left yesterday's game against Seattle after four innings and 62 pitches. He believes the injury is related to his having pitched in recent weeks with blisters on his right foot.

"I'm pretty sure I compensated somewhere with my delivery," he said. "I'm not real pleased with it. When your body starts having problems, that's the frustrating part of it. I'm pushing my body until it starts pushing back. It's pushing back a little bit."

Clemens, Cashman and Torre all refused to be specific about what the MRI showed. Clemens came the closest, saying that muscles are shutting down and "grabbing hold" of his arm.

Clemens also indicated that he had a similar injury to the one teammate Andy Pettitte had in 2004. Pettitte had a torn flexor tendon that required surgery.

It is not believed Clemens has had arm trouble since shoulder surgery in August 1985 when he was 22.

In what could well be his final season, Clemens can take risks that younger pitchers might not.

"He's so mentally tough, he gets through things that most people never get though," Cashman said. "He's a unique animal. ... He's tougher than most, but we have to play it out."

Clemens dismissed a question about his long-term prospects.