Rodriguez and the Astros avoided arbitration and reached agreement Tuesday on a $34 million, three-year contract.
The Astros said the contract will be finalized after Rodriguez takes a physical on Thursday. The deal includes a vesting option for 2014 that would increase the value to $44.5 million.
"This is one of the top left-handed starters in the game," general manager Ed Wade said. "[He was] a year away from free agency, so to be able to be able to do three years guaranteed, with a fourth-year option, made all the sense in the world for us."
Rodriguez was 11-12 with a 3.60 ERA last season. The 32-year-old lefty won eight of his last 10 decisions and had a 2.03 ERA over his final 18 starts, the best in the NL after June 24.
He is 62-64 in six seasons, all with the Astros.
Rodriguez gets a $1.5 million signing bonus and salaries of $7 million this year, $10 million in 2012 1and $13 million in 2013. The option is for $13 million with a $2.5 million buyout, and if Rodriguez is traded it becomes a player option.
Rodriguez made $5 million last year. He had asked for $10.25 million this year and the Astros offered $8 million. Rodriguez also said he wanted the Astros to make him a multiyear offer before Tuesday's team-imposed deadline to go to arbitration.
"I've been waiting for it for a long time," Rodriguez said on a conference call through an interpreter. "I was getting nervous as it was approaching. I'm very happy we were able to reach this agreement."
Rodriguez finished last season with 13 consecutive quality starts, the longest streak by an Astro since Mike Scott had 15 between the 1986 and '87 seasons.
The Astros signed Rodriguez out of the Dominican Republic in 1999. He's 34-31 over the last three seasons, and ranks sixth among left-handers in ERA (3.36) and strikeouts (502) over that span.
"Wandy has made it clear that he loves it here and he wants to be a part of the Astros," Wade said. "He's a guy who's come through our system and we're excited to be able to extend that relationship."
The Astros were not able to sign right fielder Hunter Pence to a deal and will go to arbitration. Pence, a second-round draft pick by the Astros in 2004, shook off an early season slump in 2010 to hit .282 with 25 home runs and a career-high 91 RBIs.
Pence is asking for $6.9 million next season; the Astros are offering $5.15 million. Pence made $3.5 million last season.
"We view him as a cornerstone of our ballclub," Wade said. "I'd much rather be talking about baseball accomplishments then the business side of our game. But the reality is that it is a business, and sometimes you have to go through the process, and see where it leads."