HOUSTON (AP) – Roger Clemens put off retirement once again, getting a record $18 million contract from the Houston Astros. And the Rocket didn’t rule out pitching beyond 2005.

“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, then said again that he was “99 percent” retired. But momentum built after he returned earlier this month from a Hawaiian vacation, and he asked for $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.

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 also is 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.”

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.

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.”