A team of doctors said today the blood clot that felled Houston Astro pitcher J. R. Richard cut off the flow of blood to the right side of his brain for as many as four hours but said it still was too early to know if he suffered permanent damage.

"I would say that this was a major stroke," said team physician Harold Brelsford, one of three doctors participating in an Astrodome news conference to explain Richard's condition and treatment.

The 6-foot-8 All-Star pitcher collapsed during a light workout at the Astrodome Wednesday, four days after his release from Methodist Hospital where he had undergone extensive tests to determine the cause of fatigue in his pitching arm.

Doctors who examined him for three days said he had a circulatory problem in his right arm and shoulder that did not require surgery. They said he could resume workouts but probably would be limited in the number of innings he could work in each game for the rest of the season.

But 10 minutes into his first workout, Richard, 30, collapsed and nine hours later underwent a life-saving operation that removed the blood clot from the right side of his neck that doctors now say did not develop until after his July 26 release from the hospital.

The doctors answered repeated questions about why Richard was allowed to practice so soon after his release.

"Despite finding that (the initial circulatory) blockage I don't know of any medical treatment that was necessary," said Dr. Charles McCollum, a vascular cardiologist and the doctor who led the surgical team.

"We had every reason to believe that he would develop colateral circulation and that he'd overcome the muscle fatigue he had been experiencing," said Brelsford.

It is still too early to predict whether weakness in Richard's left arm and leg will be permanent, Brelsford said. The right side of the brain, affected in Richard's case, controls nerve activities on the left side of the body, and the left side of the brain affects the right side of the body.

"We have seen people with major strokes return to almost normal activities, and J.R.'s conditioning should be in his favor," McCollum said.

Asked to evaluate Richard's condition, McCollum said, "He still has marked weakness . . . It may be transient or it may be permanent. He has shown improvement of motor functions.