The Rangers targeted Treanor as their backup catcher from the beginning of the off-season after he played an integral part of helping them reach the World Series for the first time in club history.
"We appreciated the qualities that Matt brought to our club in 2010, both on the field and the presence he had in our clubhouse," said Rangers general manager Jon Daniels in the official release. "He stepped into a challenging situation and helped lead the club. We're happy to have him back to solidify our catching situation."
To make room on the 40-man roster, the Rangers outrighted pitcher Ryan Tucker to Triple-A Round Rock. The Rangers still have a full 40-man roster.
The move comes on a day when the Rangers, Yankees and the rest of the world are waiting to see if Cliff Lee will make a decision on where he will pitch next season and beyond. The Rangers are also waiting on Lee before completing their negotiations with Vladimir Guerrero to return as their designated hitter.
Treanor, who was acquired from the Brewers late in Spring Training, played in 82 games for the Rangers in 2010 and batted .211 with five home runs and 27 RBIs in 237 at-bats. He is primarily known for his defense and ability to handle pitchers.
Rangers pitchers had a 3.92 ERA with Treanor behind the plate, the fourth lowest among American League catchers with 80 games played. He started 67 games, the most by any Rangers catcher. His 82 games and 237 at-bats were career highs in his seven-year Major League tenure.
"I felt I contributed to the club when we were in a position to make the playoffs," Treanor said. "To play that many games, I felt I could come back even stronger this year. It was a mental-builder for me."
Treanor, who will be 35 in March, understands that he will likely be the backup behind Torrealba this coming season.
"You've got to know who you are to reach your potential as far as the club is concerned," Treanor said. "I played 82 games, the most in my career and I'll be ready for whatever happens. Being in a backup role doesn't mean you're just sitting on the bench or catching bullpens. You have to take an active part in the game.
"They made a move to sign Yorvit to make the team stronger. Everybody's goal is to get back to the World Series and have a chance to win it."
The Rangers still have Taylor Teagarden and Max Ramirez on their roster and both are playing winter ball. Teagarden is 5-for-31 with two home runs and three RBIs over 10 games in the Dominican Republic, while Ramirez is 41-for-135 (.305) with two home runs and 13 RBIs in Venezuela.
Torrealba signed a two-year, $6.25 million contract with the Rangers on Nov. 29. He is a 10-year Major League veteran who spent last season with the Padres.
Torrealba started 89 games for the Padres in 2010 and had a catcher's ERA of 3.14, the lowest in franchise history (minimum 81 games) and the lowest in the Majors since Paul Lo Duca had a 3.14 ERA for the Dodgers in 2003.
At the plate, Torrealba hit .271 with seven home runs and 37 RBIs in 325 at-bats. He also had a .343 on-base percentage. He hit a career-high .291 with a .351 on-base percentage with the Rockies in 2009.
"I only know playing against him in the National League," Treanor said. "But being a catcher, I have a lot of respect for front-line guys. I can't wait to meet him. Hopefully we'll have the same type of camaraderie and be able to help the pitching staff."