Whalen was recalled from Triple-A Tacoma on Saturday, the Tacoma News Tribune's Bob Dutton reports.
Whalen was working as a starter in Tacoma, but he's not believed to be in the mix for Sunday's opening in the rotation. However, he could piggyback off Chase De Jong's start Saturday or come in after Christian Bergman or Dillon Overton start Sunday. The 23-year-old righty profiles as a long reliever or swing man.