The Mariners created five openings on their 40-man roster on Thursday afternoon.
Infielder-outfielder Bryan LaHair, left-handed pitcher Cesar Jimenez and right-handers Randy Messenger and Marwin Vega all were outrighted to Triple-A Tacoma. Left-handed reliever Justin Thomas was claimed off waivers by the Pirates.
LaHair, Jimenez and Messenger are eligible for six-year Minor League free agency.
LaHair, who turns 27 on Nov. 5, spent all of last season with Tacoma. He hit .289 with 28 doubles, 26 home runs and 85 RBI in 121 games. A first baseman for most of his career, which includes 45 games with the Mariners in 2008, he mostly played in left field this season.
Messenger helped the Rainiers capture the Pacific Coast League North Division title with 28 saves before being promoted to the Mariners in September. He made 12 relief appearances, posting a 0-1 record and 4.35 ERA, holding the opponents scoreless in eight of those outings.
Vega, signed as a non-drafted free agent in 2003, split last season between Class A High Desert and Double-A West Tennessee, going a combined 0-3 in 26 appearances.
Jimenez and Thomas both pitched for the Mariners in '08, but not last season.
Jimenez, 24, missed the entire season with biceps tendinitis while Thomas had a 2-4 record and 4.48 ERA and six saves in 53 games for Tacoma.
Jim Street is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.