Tomko was recalled Wednesday, along with catcher Taylor Teagarden, after the Rangers put rookie right-handed reliever Mason Tobin on the disabled list and optioned left-hander Michael Kirkman to Round Rock.
The 38-year-old Tomko is trying to come back from a nerve problem in his right arm. He went to spring training on a minor-league deal with the Rangers. His last major-league game was a five-hit shutout victory for Oakland at Texas on Sept. 14, 2009.
Tobin came out of Tuesday night's game against the Los Angeles Angels with pain in his right elbow.