Whalen (shoulder) was placed on the 7-day DL at Triple-A Tacoma on Tuesday, Rainiers play-by-play broadcaster Mike Curto reports.
Whalen leads the Rainiers with seven wins, which he's garnered over 14 starts. Curto reports that Whalen left his most recent start against Salt Lake last Thursday with shoulder stiffness, which led to Tuesday's move. The 24-year-old has made one appearance at the big-league level this season as well, firing four scoreless innings during which he allowed a hit and a walk against the Red Sox on June 15.