The 43-year-old Clemens, who will be entering his 23rd major league season, is agreeing first to a minor league deal that pays $322,000 over the five-month minor league season. His first start is likely to be at Lexington, Ky., the Class-A team where his oldest son, Koby, plays.
If all goes well, his second start would be June 11 at Double-A Corpus Christi, Texas, followed by a start June 16 at Triple-A Round Rock, Texas. He could be pitching in the big leagues by June 22.
"The ball's in my court now," Clemens said Wednesday at a news conference to announce his return. "This was a difficult decision on my part in a number of situations. I have to now take the next step and get my body ready to come back, get effective, win games."
Even with an abbreviated season ahead, Clemens is uncertain how he'll hold up physically.
"I can get into a game situation and my body not respond like I want it to," he said. "I pushed my body hard, but I still need to get some competitive innings, stressful innings.
"I call them stressful innings because, at my age, it's stressful."
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 $12,632,307.
"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."
The Astros were 27-26 and 6 1/2 games behind the NL Central-leading Cardinals after Tuesday night's 6-3 victory at St. Louis.
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!!!"
Clemens led the majors with a 1.87 ERA last season and helped the Astros reach their first World Series. Houston, the New York Yankees, Boston and Texas all tried to lure him this season.
Clemens said his son was a deciding factor in choosing the Astros. Koby Clemens has been rehabbing since breaking his left pinkie on a slide. But he and his father will fly to Lexington on Thursday, and Koby will be taken off the disabled list by the end of the weekend.
"Yeah, Koby is the wild card in all this," Clemens said. "Just like he told me this morning, even if he was somewhere else, we've had too many great moments here the last two years to set that aside."
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.
In Detroit, New York Yankees manager Joe Torre said Tuesday that it made sense for Clemens to return to Houston.
"I'm not at all surprised," Torre said. "I didn't think that him coming back here was ever going to happen. Houston's just such a perfect fit for him — he lives there and Andy's on the team. That's why he came back before, and the circumstances haven't changed."
The Red Sox issued a statement after Clemens announced his return to Houston.
"Although we are disappointed that Roger Clemens will not be joining the Red Sox, we are glad that we went through the process and reconnected as an organization with Roger," the team said. "We wish him the best of luck with Houston and in the National League. When Roger's career does come to an end, we will welcome him to Fenway Park and will forever consider him to be a legendary and beloved member of the Boston Red Sox."
Texas owner Tom Hicks was told last week by Clemens' agents that the Rangers were out of consideration, general manager Jon Daniels said.
"Tom got the call on Friday that we were no longer in the running for his services," Daniels said Tuesday. "The way we looked at it was, it would be an honor to be associated with him but we've continued to focus on the 25 guys here. It would have been nice, but we weren't planning on it from the get-go."
Clemens 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).