To make room for Wilhelmsen, Seattle optioned right-hander Jonathan Aro to Triple-A Tacoma and transferred Charlie Furbush to the 60-day disabled list.
Wilhelmsen, 32, was the Mariners' primary closer in 2012-13, saving a combined 53 games. He was 2-2 with 13 saves and a 3.19 ERA in 53 games with Seattle last season before being dealt to Texas in a November trade that brought Leonys Martin to the Mariners.
Wilhelmsen struggled with the Rangers this season, going 2-3 with a 10.55 in 21 appearances.
Quinn Roberts is a reporter for MLB.