DENVER -- Jon Lester had cancer. Lymphoma, to be exact, but cancer. Whatever the exact name, you don't want it.
The same goes for blood clots. Aaron Cook can tell you all about them. He had them in his lungs.
Sunday evening, in Game 4 of the World Series, a cancer survivor and a blood clot survivor will take turns on the Coors Field mound. Lester can give the Boston Red Sox their second world championship (and second sweep) in the past four years. Cook can keep the Colorado Rockies from becoming a postseason footnote and oh-fer victim.
Two pitchers. Two men who weren't entirely sure -- how could they be? -- that they'd ever play baseball again. And now one of them can help end a World Series and the other can help extend it.
"You know, I'm just trying to take it as another start, trying not to look at it as anything extra than that," said quiet, unassuming Lester.
But it isn't just another start, is it? A World Series is at stake, but what makes it an extraordinary night is the convergence of circumstances that brings Lester and Cook to this moment.
"I don't think it's a coincidence," said Rockies manager Clint Hurdle. "I think this game drips with irony at different times for different reasons, and it's not just because of the game or the manager matching pitchers."
Maybe, as Hurdle said, "God's fingerprints" were all over this one. Or maybe it was simply two guys who got lucky. Whatever the reasons, they're here.
Neither player was a lock to start Game 4. Lester wasn't added to the Red Sox rotation until a shoulder and back injury to veteran knuckleballer Tim Wakefield forced manager Terry Francona to reluctantly drop Wakefield from the World Series roster. The decision to use Cook wasn't made until he convinced Hurdle he had recovered sufficiently from an oblique injury.
"It is kind of ironic with him going through what he went through and me what I went through, both of us to work our way back to the top level of professional baseball," Cook said. "It's tough enough to get here, and what we've been through just to keep our focus, keep our faith and just realize that baseball is not the most important thing."
But it's the thing that kept them going. Lester was first diagnosed with a rare form of non-Hodgkin's lymphoma in September 2006, near the end of his wonderful rookie season. He began chemotherapy that same month, and by December, his doctors no longer could detect any cancer.
The Red Sox hoped for the best. Lester didn't. He said he never considered a scenario that would prevent him from complete recovery, from imagining a moment like the one he'll experience Sunday night at Coors Field.
"That's not my mentality," Lester said. "I'm a competitor. I don't want to be down with anything. I just try to take that mentality into it. Don't feel sorry for yourself. Don't sit at home and think about it."
So he went fishing. He hunted. "I just tried to do that and keep my mind off the other stuff and tried to be as normal as I could," he said.
Normal to Lester is playing baseball. The Red Sox admired his optimism, but they weren't counting on anything. Even when Lester arrived at spring training, the team's expectations were simple: Expect nothing. Anything else would be a pleasant surprise.
"What he went through was a very difficult winter, I'm sure, for he and his family," said Francona. "He handled it with grace, a lot of dignity, a lot of perseverance, and because of that [and] some really neat medical people, the fact that we're even talking about baseball is really awesome. I think before Jon picked up a ball this year, it was already a successful year."
Lester began the season with Class A Greenville. Then Triple-A Pawtucket. His 2007 big league debut didn't come until July 23 against the Cleveland Indians, when he won a major league game for the first time since Aug. 23, 2006. You could hear the cheers all the way back from his hometown of Puyallup, Wash.
The guy is undefeated in the majors this season. One more win and the Red Sox break out the swim goggles and start spraying champagne.
"Last year, I didn't really get a chance to enjoy what was going on, and being up in the big leagues, being a part of every kid's dream and playing up there with these guys," Lester said. "I took a lot of things for granted last year and beat myself up over little things. This year, I've tried to just have fun, treat it like a game, like a kid's game, have fun doing it, and I think it's helped out quite a bit."
It also helps to be healthy. Cook knows the feeling.
I feel pretty comfortable with where I'm at, and [Sunday night] will be the real test. It's the biggest stage.
During a late 2004 start, he experienced dizziness on the mound. Doctors discovered that one of his ribs was pressing against a vein and that the odd condition was creating life-threatening blood clots. He wouldn't pitch again for nearly a year.
Cook recovered. He returned in 2005 and won six consecutive games. His story was as inspirational as Lester's is now.
"There's a verse in the Bible that says, 'Consider it pure joy, my brothers, whenever you face trials of many kinds because testing of your faith develops perseverance,'" said Cook, the Rockies' 2007 Opening Day starter. "That's one verse I really held on to."
Cook and the Rockies face the postseason's most difficult trial: an 0-3 deficit and the sobering truth that they have to win four consecutive games against a Red Sox team on a 7-0 World Series victory run. They'll need more than faith to do that. They'll need Cook to last longer than the 2 2/3 innings starter Josh Fogg (10 hits, six runs) lasted in Saturday night's 10-5 loss.
Otherwise, when the Coors Field public-address announcer asks the crowd for its fourth-inning music request, as he did a night earlier, the crowd might ask for "Taps."
Cook won't have it easy. The Rockies have scored a grand total of seven runs in three games. And because of the muscle strain, he was left off the NLCS roster and hasn't pitched in a big league game since Aug. 10.
"I feel pretty comfortable with where I'm at, and [Sunday night] will be the real test," Cook said. "It's the biggest stage."
Funny, Lester said the same thing. Figures. Survivors are like that.
Gene Wojciechowski is the senior national columnist for ESPN.com. You can contact him at email@example.com. He co-authored Jerome Bettis' autobiography, "The Bus: My Life In and Out of a Helmet," which is available now.