The Rangers have acquired right-hander Miles Mikolas from Pittsburgh in exchange for first baseman Chris McGuinness.
The deal Monday came three days after Texas designated McGuinness for assignment to clear room on its roster after free-agent outfielder Shin-Soo Choo signed a $130 million, seven-year deal.
Mikolas spent most of 2013 at Triple-A Tucson, going 4-2 with 26 saves and a 3.25 ERA in 54 games. He was designated for assignment by the Padres in November, then traded to Pittsburgh.
McGuiness hit .176 with one RBI in 10 games for Texas last season. He hit .246 with 11 home runs, and 63 RBI in 104 games at Triple-A Round Rock.
To make room on their 40-man roster for Mikolas, the Rangers designated outfielder Rafael Ortega for assignment.