Aardsma, who missed the last two weeks of 2010 and all of Spring Training because of a hip problem that was corrected by surgery in the offseason, hadn't thrown a baseball since spraining the ulnar collateral ligament in his right elbow during a rehab assignment with Triple-A Tacoma last month.
He did so in the Safeco Field outfield on Monday and said things went about as smoothly as they could have gone.
"Obviously, you're trying to think positively about everything," said Aardsma, who saved 31 games last year and 38 in 2009. "You're going to have your reservations, but it went well. I'm not sitting there thinking about every throw, but it's hard not to. We weren't pushing it."
Aardsma said he'll take a day off from throwing before trying again Wednesday.
"We'll go from there," he said. "Maybe we'll try to push it a little more, but it will just be a progression."