Swanson, who was just optioned to Triple-A Tacoma on Friday, is a candidate to be called up if Wade LeBlanc (oblique) is forced to miss at least one start, Greg Johns of MLB.com reports.
It could be quick turnaround for Swanson if LeBlanc's MRI on Saturday confirms that he'll need to miss at least his next scheduled turn in the rotation Wednesday versus the Indians. Swanson appeared in one game for the Mariners during his just-concluded big-league stint, allowing two earned runs on three hits and two walks while recording four strikeouts over two innings against the Royals on Thursday.