The Astros will receive two mid-tier prospects in the deal, though there has been no word on who they may be.
The 37-year-old Rodriguez played for the Rangers from 1991-2002, earning All-Star and Gold Glove honors for 10 consecutive seasons and winning the American League MVP in 1999. Rodriguez helped guide the Rangers to AL West titles in 1996, 1998 and 1999. He caught 1,426 games in Texas, second in club history to Jim Sundberg's 1,495. He hit .305 with 215 home runs and 829 RBIs with the Rangers. He left when the club refused to offer salary arbitration after the 2002 season.
Since then, Rodriguez has played for the Marlins (helping them win the World Series in 2003), Tigers, Yankees and Astros. His offensive prowess has faded over the last few seasons. This year he's hitting .251 with eight home runs, 34 RBIs and 41 runs in 327 at-bats.
Rangers outfielder David Murphy said he will give up his No. 7, which Rodriguez wore throughout his time with the Rangers and much of his career. Murphy said he'll switch to No. 14.
In addition to the Rodriguez move, the Rangers placed infielder Esteban German on the disabled list with a right groin strain, retroactive to Friday. The team recalled right-handed reliever Guillermo Moscoso from Triple-A Oklahoma to fill his spot on the active roster.
Moscoso was 5-3 with a 2.17 ERA in 10 games with Oklahoma. He has made five relief appearances for the Rangers, allowing four earned runs in 8 1/3 innings.