But before getting a chance to walk out to the bullpen for the series finale against the Tigers, he was optioned to Triple-A Tacoma, creating a spot on the 25-man roster for Bill Hall, acquired from the Brewers on Wednesday.
"We would like for him to go down and possibly start there for the short term," manager Don Wakamatsu said. "We have been making some mechanical changes with him and feel we are headed in the right direction now. We look to have him stretched out and bring him back in September."
Olson had a 3-5 record and 5.88 ERA in 24 appearances, including 11 starts, with Seattle this season.
He was acquired from the Cubs, along with infielder Ronny Cedeno, on Jan. 28 for pitcher Aaron Heilman.
Jim Street is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.