"I always leave that percentage point open because you never know," Clemens said Friday after agreeing to a one-year deal that gives him the highest salary for a pitcher in baseball history.
His incentive to stick around could be a chance to pitch against his 18-year-old son.
"Today, I was walking out the door and my oldest one, Koby, said, 'Dad, don't say something, anything, about retiring, because I might be in the big leagues in a couple of years and I want a piece of you,'" Clemens said in a tone that was half-serious and half-humorous.
"That might have to be a comeback," added the seven-time Cy Young Award winner, who turns 43 in August.
The 10-time All-Star helped the Astros come within one win of the first World Series appearance in the 43-year history of the franchise. After losing Carlos Beltran, Jeff Kent and Wade Miller, and with the prospect of Lance Berkman not being ready for Opening Day following knee surgery, the Astros desperately needed some good news.
"It kind of gives everybody a feeling of invincibility, that confidence level when you walk on the field," Astros manager Phil Garner said. "A guy like him, he can really make a difference all over the club. It's one of those intangibles that you've got to have."
Clemens, whose salary tops the $17.5 million Pedro Martinez earned with Boston last year in the option year of his contract, first retired after pitching for the New York Yankees in the 2003 World Series. But he changed his mind and agreed on Jan. 12 last year to join his hometown Astros, accepting a $5 million, one-year deal.
He earned $1,825,000 in bonuses based largely on Houston's home attendance before saying again that he was "99 percent" retired. But momentum built after he returned earlier this month from a Hawaiian
vacation, and he asked for a $22 million salary -- matching his uniform number -- when proposed figures for salary arbitration were filed Tuesday. Houston offered $13.5 million, leaving the midpoint at $17.75 million.
"I kind of sat back and laughed at the numbers," he said.
Clemens' agents, Alan and Randy Hendricks, then negotiated the deal with the Astros on Wednesday and Thursday.
"I thank my family. Last night there were some smiles, there were some tears," Clemens, dressed in a black T-shirt, said at a news conference on the Minute Maid Park field, adding that sons Koby and Kory helped talk him into playing again.
"Just remember what it sounded like here, Dad, when you took the mound and what it sounded like during the playoffs when we were winning," Clemens said they told him. "Baseball captured this city in a so-called football town."
He wistfully remembered being honored at halftime of a Houston Texans' game in November.
"You got 60,000 people chanting, 'One more year!' That stuck with me," he said.
Clemens agreed to a contract that makes him the highest-paid pitcher for the fifth time, following deals with Boston in 1989 ($2.5 million average), with the Red Sox in 1991 ($5.38 million), with Toronto in December 1996 ($8.25 million) and with the Yankees in August 2000 ($15.45 million). The two contracts with Boston and the one with New York made him the sport's highest-paid player overall.
Clemens is also getting the highest one-year contract in baseball history, topping Greg Maddux's $14.75 million deal with Atlanta in 2003.
His decision to stay is one of the few bright spots in an otherwise miserable offseason for the Astros.
"Sure, I was hurt a little bit. I don't think losing Beltran, Carlos, was that bad, but you lose Kent also, so you lose a lot of power, a lot of numbers," Clemens said. "But again, it's time for some people to step up."
Astros general manager Tim Purpura, speaking at home plate in front of an Astros logo background that toppled over from a gust of wind, said the team was in negotiations with free-agent reliever John Franco, who would add a much-needed left-hander to the bullpen.
"I think John is trying to make up his mind whether to come here or consider some other offers," Purpura said. "I hope to know within the next day or so whether he's going to come here. We're definitely strong on John."
Clemens is 10th on the career wins list with 328, one behind Steve Carlton. Clemens' 4,317 strikeouts are second to Nolan Ryan's 5,714.
His decision to sign with Houston last year was spurred by former Yankees teammate Andy Pettitte, who left New York to sign with the Astros. Clemens went 18-4 with a 2.98 ERA and 218 strikeouts, winning his first Cy Young in the NL, but Pettitte hurt an elbow tendon while batting in his first start, was largely ineffective and had season-ending surgery in August.
"Really, we didn't have the opportunity to perform together," said Clemens, who spoke with Pettitte on Friday. "It's time to do it again -- and who's to say that we can't?"
At $18 million, Clemens tied Sammy Sosa and Barry Bonds for the fourth-highest average salary in the major leagues, trailing only Alex Rodriguez ($25.2 million), Manny Ramirez ($20 million) and Derek Jeter ($18.9 million).
"I take a deep breath, and here we go again," Clemens said. "I'm ready for the challenge."