Clemens first retired after the 2003 season, then changed his mind and joined his hometown Astros after former Yankees teammate Andy Pettitte left New York to sign with Houston. The seven-time Cy Young Award winner said he was “99 percent” retired after 2004, but he came back for Houston’s 2005 run to the World Series.

Then, after the Astros were swept by the Chicago White Sox, Clemens again said he considered himself retired. But he never formally said farewell to baseball and always left open the possibility of returning, even pitching for the United States in the World Baseball Classic.

When he is added to the major league roster, he gets a one-year contract worth $22,000,022 — his uniform number is 22. Because he won’t be playing the full season, he gets only a prorated percentage of that, which would come to about $12.25 million if he rejoins Houston in late June.

The tentative goal is to have him start against Minnesota on June 22 — if he’s put on the big league roster on that day, he would earn $$12,262,307.

“I’m not riding around in the back of a convertible, waving my hat and selling tickets,” he said. “They expect me to get on the field and win ballgames and do it the way they’re used to seeing me do it.

“And I accept that more so than anyone.”

Houston was finishing its series with the Cardinals on Wednesday afternoon, but the video scoreboard at empty Minute Maid Park was already flashing “The Rocket is Back!!!”

General manager Tim Purpura said Clemens didn’t agree to the deal until after midnight, early Wednesday morning.

“It’s a tremendous uplift to our situation,” Purpura said. “Our young pitching has been tremendous, but our young pitching is inexperienced. What we want to do is get back to the playoffs, we want to get back to the World Series and Roger Clemens’ presence in our rotation will certainly do a lot to get us there.”

Clemens led the majors with a 1.87 ERA last season. Houston, the New York Yankees, Boston and Texas all tried to lure him this season.

“It was very flattering and a piece of my heart is in each of those cities,” he said. “I think all four teams, including ours, come September, are going to be right in the middle of things. In that sense, I was pretty lucky to have those teams talk to me.”

Rangers owner Tom Hicks sent Clemens a handwritten note this week. The Rangers, meanwhile, moved forward without him.

“He’s the greatest pitcher of all time, and it’s always exciting when he’s pitching,” Rangers star Mark Teixeira said. “But he’s not pitching for us, so we don’t worry about it.”

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Boston manager Terry Francona was just happy his team won’t have to face Clemens any time soon.

“I’m glad he didn’t go to the Yankees,” Francona said. “Let him stay in the National League.”

Yankees manager Joe Torre said Clemens “still possesses that little boy inside himself and that’s why he keeps wanting to play this game.”

“And he doesn’t have to apologize because he’s still a dominant pitcher,” he said.

“It makes sense for him to go back with everything that he’s used to over there the last couple of years. Maybe not pitching the first part of the year will be a benefit to him because he kind of wore down toward the end of last year.”

Clemens last pitched competitively in the WBC, where he beat South Africa in the first round and lost to Mexico 2-1 in the second round on March 16.

He won his seventh Cy Young Award — first in the NL — in 2004, going 18-4 with a 2.98 ERA. He went 13-8 last year, winning the major league ERA title for the first time since 1990.

Clemens has a career record of 341-172 with a 3.12 ERA and 4,502 strikeouts, pitching for Boston, Toronto, the Yankees and Astros. An 11-time All-Star and winner of the 1986 AL MVP Award, he is tied for eighth on the career wins list and is second in strikeouts behind Nolan Ryan (5,714).