But he was single then. He had met Farrah Stone Johnson while rehabbing in 2007. They didn't marry until 2009 and Hudson came along the following year.
"You begin to think, 'What if he gets sick like I did, what we'd go through like what my parents went through,'" Lester said. "You hope it's something he'll never have to experience."
That evolved into his launching in May of NVRQT (it stands for "Never Quit"), a foundation to raise awareness and funds for pediatric cancer research.
"Once your son comes into the world and you look at him and imagine him to go through what I went through, it's heartbreaking," Lester said at the Fenway Park announcement.
"That was another reason for me getting involved with this. I couldn't imagine him being in a hospital bed getting the drugs I got. Any way that we can help raise money so kids can get this treatment as painless and easy as possible, the better."
One word often related to cancer is battle -- a patient battling the disease. In fact, it's the researchers and doctors who wage the battle. For the patient, Lester said, the struggle is more mental.
"When you have pneumonia or the flu you can get Theraflu or Tylenol Sinus or something, and you feel some relief," he said. "When you're going through chemo, you don't feel relief. You don't know if it's working. You don't know if the cancer's going away or still there.
"I went through four treatments before I found anything out. I'm talking about from September through the first week of December not knowing if anything is working."
One of the things Lester was able to do fairly well, he said, was separate the treatments from the rest of his life, doing what he normally did in the offseason, like working out, throwing and fishing and hunting. "I think that helped keep me sane," he said.
He showed up in Fort Myers, Fla., for Spring Training in 2007 about 50 pounds below his playing weight of 240.
"I'd say I looked like a 12-year-old with no hair. And I thought I had a chance," to make the Opening Day roster.
"I thought my body was in a different place than it was. I was stupid."
The Red Sox limited him to pitching in intrasquad and B games, then sent him to Class A. He made three starts for the Greenville Drive and one at Double-A Portland preceded 14 at Triple-A Pawtucket -- then frustration set in when another southpaw was called up in June to fill in for injured Curt Schilling.
Lester finally made it back on July 23, pitching six innings (five hits, two runs, three strikeouts) in a win at Cleveland. He finished the year 4-0; the Red Sox won nine of his 12 starts.
He also was the winning pitcher in their 2007 World Series-clinching Game 4 sweep of Colorado. The following season he received the Hutch award, given to the player who best exemplifies the fighting sprit and competitive desire of the late pitcher and manager Fred Hutchinson.
"He's definitely an inspiration to all of us," Jonathan Papelbon, then the Red Sox closer, said of Lester when he returned to action against the Indians in 2007. "We all go through ups and down in life, and he went through a really big down in life and was able to fight through it and come back."
Bruce Lowitt is a freelance writer based in Tampa, Fla.