Lester, who was reported to have enlarged lymph nodes in his back earlier this week, was diagnosed yesterday with a treatable form of anaplastic large cell lymphoma. The condition is a form of non-Hodgkin lymphoma.

Within the coming week, according the organization, the 22-year-old pitcher will begin treatment, which figures to include chemotherapy. Since the condition is classified as a high-grade lymphoma (fast growing) it is believed that any treatment will be aggressive.

"Today's news regarding Jon Lester is a personal matter, so we will refrain from commenting other than to say we care deeply about Jon and will support him through this difficult period," Red Sox general manager Theo Epstein said in a written statement distributed before Boston's 2-1 win over Toronto last night. "The thoughts and prayers of the entire Red Sox organization are with Jon and his family."

It is unknown what stage lymphoma Lester has. Stage 1 is considered the most curable, residing in just one particular area of the body, whereas Stage 4 is the worst, suggesting the lymphoma has spread beyond the lymph nodes to other lymphatic organs.

"The location doesn't usually have an effect on what kind of disease it is," said Dr. Yaul Kouri, a medical oncologist at Lawrence General Hospital. "But what does have an effect is how many different spots it is found in. And the other thing is if the lymphoma is found in the bone marrow or other organs, than it can be worse. Nevertheless, it is still treatable and potentially curable. The lower the stage the better the outcome."

Lester was placed on the 15-day disabled list after his last start Aug. 23 in Anaheim against the Angels. The outing produced a five-inning, six-hit, three-run win, improving to 7-2. He holds a 4.76 ERA with 60 strikeouts in 811/3 innings.

For now, baseball will be put on the back burner.

"You probably can't do athletic competition," said Dr. Kouri, referring to Lester while in treatment. "He will probably have to take some time off of that."

"It's nice for us to win, but it's a game," said Sox reliever Mike Timlin. "It's fun to go out there and play, but when you play with things like that in the back of your head it's tough. This was kind of win for him, and hopefully this gives him some encouragement."

The world of sports features several cancer-surviving athletes, including Mario Lemeuix (Hodgkin's disease), Andres Galarraga (non-Hodgkin's lymphoma), Mike Lowell (testicular cancer), Joe Torre (prostate cancer), Scott Radinsky (Hodgkin's disease), John Kruk (testicular cancer), Eric Davis (colon cancer), Daryl Strawberry (colon cancer) and Lance Armstrong (testicular cancer).

Red Sox trainer Paul Lessard was also diagnosed with testicular cancer in April.

"I think the best thing is if the doctor's diagnosis is that it's treatable and curable, take it for what it's worth," said Lowell, who was diagnosed with cancer in 1999. "Get well and worry about baseball later."

"It's his life," Timlin said Thursday. "It's not him being able to get out of the sixth inning. He's 22. That's a long future not to have if you come up with an illness that you can't get rid of. So we are praying for him.

"Winning baseball games, yeah, that's great. Losing baseball games, no, that's not very much fun. But dealing with horrible things in human life, that's a whole lot worse than losing."