The Astros are banking that he can do it in the postseason again.
Oswalt will make the first start of his second postseason when Houston and Atlanta tangle in Game 3 of what essentially has become a best-of-three National League Division Series. The first pitch is scheduled for 7:05 p.m. CT on Saturday night, but Oswalt had his game face on early.
"Pressure's always on me, it seems," he said after Friday's off-day workout. "But I like big games."
Game 3 certainly qualifies, but it will not be the first playoff-type game that Oswalt has pitched this month. He capped his second consecutive 20-win season on Oct. 2 here at Minute Maid Park, pitching the Astros to a 6-4 win over the Cubs in a must-win game that clinched the NL Wild Card.
While Andy Pettitte and Roger Clemens get all of the attention, an argument can be made that Oswalt is the Astros' ace. He went 20-12 with a 2.94 ERA in a career-high 241 2/3 innings during the regular season and became the first Major Leaguer to notch consecutive 20-win seasons since Arizona teammates Randy Johnson and Curt Schilling each did it in 2001-2002.
"That's not a fluke," Houston manager Phil Garner said. "He's pitched well enough to be that 20-game winner for us."
This time, Oswalt enters the postseason with some experience. He pitched in four games as the Astros played to a Game 7 of the 2004 National League Championship Series in St. Louis, going 1-0 with a 4.19 ERA. His postseason debut came in Game 2 of last year's NLDS, when Oswalt worked eight innings and limited the Braves to one run in an eventual extra-inning Astros loss.
How will that experience play in this series?
"It gives you confidence," said Oswalt, 28. "You don't have to calm your nerves down as much [as] if it's your first one. So hopefully we get a few runs early off the new guy with Atlanta [Jorge Sosa], kind of get him rattled early."
The way Garner sees it, last year's postseason run could only have made Oswalt better.
"We're on the big stage now," Garner said. "When things go well, everybody in the world is watching it. When things don't go so well, everybody's watching that, too."
During the regular season, things went exceptionally well for Oswalt.
He became the first Astro to notch consecutive 20-win campaigns since Joe Niekro in 1979-1980 and along the way made his first career All-Star team, selected by fans via MLB.com balloting.
Oswalt surrendered two or fewer runs in 18 of his final 28 starts and finished fourth in the league with 25 quality starts (six or more innings and three or fewer earned runs). He went 12-2 with a 2.52 ERA at home and his .680 career winning percentage (83-39) ranks ninth all-time among pitchers with at least 100 decisions.
So why does he seem to fly so low on the radar? Oswalt always seems to come up third in talk about Houston's "big three" starters, and more than a few fans still mispronounce his last name (it's OWES-walt).
"He's not underrated by the hitters in the National League, I'll tell you that," said Astros catcher Brad Ausmus. "The media may not pay as much attention to him, but the rest of the league does. He doesn't get a lot of the attention he deserves, and maybe that's a good thing."
"I don't think he's going to run for political office anytime soon," Garner said carefully. "He enjoys pitching. He enjoys his private life. He enjoys, I think, going back to his hometown when the baseball season is over."
But when the baseball season is on, Oswalt is a bulldog.
"He's never been intimidated or star-struck by the big-league atmosphere," Ausmus said.
Garner said Oswalt evolved into more of a pitcher this season instead of a young thrower. His 94-96 mph fastball is as good as anyone's, but it's made even better by the 65-67 bender that ranks among the league's nastiest pitches. Some opponents call it a changeup, some call it a curveball, and almost all of them call it "filthy."
"Last year, he was rearing back and throwing the ball," Garner said. "He was in the top of the strike zone a lot, threw a lot of pitches to get deep in the game. This year, he's been a little more efficient, thrown fewer pitches, got us deeper in the game."
Garner thinks he'll become even better.
"I still think he's going to learn how to focus," Garner said. "Sometimes, if there's anything that he doesn't do now that you see a [Clemens] or a Pettitte do, it's maybe [because] there are times he doesn't focus. It's not a lack of ability or lack of skill, I just think that sometimes he needs to focus. It's a process that all young pitchers learn, focus for nine innings and go out with intent for nine innings."
Oswalt has tinkered with his mechanics of late, and said he felt unusually fatigued after about four innings of the regular-season finale. Don't expect either factor to affect his mindset going into Saturday night.
"I don't treat any game as, 'I'm going to lose a game.' Doesn't matter if it's the first game of Spring Training or last game of the season, I don't want to lose. I never have been a real good loser -- my wife can tell you guys that."
Adam McCalvy is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.