Ryan, 33, had been erratic in 25 appearances (20 2/3 innings) this season and had not pitched since giving up a three-run homer to Hideki Matsui in a 10-8 loss to the New York Yankees on Sunday, his second appearance in eight days.
Toronto signed him to a five-year contract, $47 million before the 2006 season.
Injuries and command problems had plagued the left hander came to Toronto as a free agent in November of 2005 after spending the previous six seasons with Baltimore.
He underwent Tommy John elbow surgery and missed the 2007 season.
"It's been hard to find spots for him to pitch," Manager Cito Gaston said on the team's Web site on Monday.
"It's frustrating when you sit and you wait to pitch and you get in there and you don't do good," Ryan said.