Not long after he was diagnosed last year with a treatable form of lymphoma, Lester received a handwritten note from Lance Armstrong, the seven-time Tour de France champion, who overcame testicular cancer.
"I was kind of surprised,'' said Lester, who on Monday won his first major league start in 11 months since being diagnosed with the disease. "I've got it hanging up in the house, it was real nice. He sent me his book and a picture, too.''
Lester triumphed in his return to the mound, allowing two runs and five hits in six innings of Boston's 6-2 win over the Cleveland Indians.
He said Armstrong's note was one of many that inspired him.
"It meant a lot,'' he said. "I was really excited about it.''
The 23-year-old underwent six chemotherapy treatments near his home in Tacoma, Wash., before learning in December that he had beaten anaplastic large cell lymphoma, an illness that was found on a routine visit to the doctor's office for back pain.
Lester had gotten off to a 7-2 start as a rookie when he was diagnosed, ending his season.
His journey back to the majors was a challenging one, a long route to which Armstrong could relate.
"It's very difficult,'' Armstrong told the Associated Press. "Physically it's difficult. The body has clearly gone through a traumatic, difficult time, and emotionally it's probably very difficult for him as well.
"It was hard for me. You don't look at your life the same ever again. You don't look at a baseball game the same way again, you don't look at a pitch the same again. So things are put into perspective quickly.''
Lester's comeback win came with his parents, John and Kathie, sitting near the Red Sox dugout. After the game, the family gathered for an emotional celebration.
"It was great,'' Lester said before Tuesday's game. "I was pretty wore out so I think they were more excited than I was at the time. I think they had a good time. But I think they're a little embarrassed because they got a lot of TV time.''
The Lesters, who traveled from their home in Puyallup, Wash., were interviewed by a reporter during the game, and it was apparent from the emotion in their voices that seeing their son back in a big-league game filled them with pride, joy and love.
Lester's parents cheered for every pitch and every out, and Kathie could barely watch in the fourth inning when the Indians loaded the bases before Lester wriggled out of the jam.
"When I pitch they get pretty emotional,'' Lester said. "That's the first time I've seen their reaction during a game before. I watched them on the highlights.''
Lester received hundreds of letters like Armstrong's during the months he spent fighting cancer. And following his win, he was inundated with phone calls from well wishers.
"It's starting to sink in a little bit now,'' he said. "The phone has been ringing quite a bit. I've been more or less trying to hit the ignore button for now and just kind of catch up on what's going on around here.''