The Blue Jays will need to make a corresponding move when Wells reports to the team. They announced the waiver claim during a rain delay in Detroit on Wednesday.
Seattle designated Wells for assignment March 31, when the Mariners kept Jason Bay as a backup outfielder. Wells hit .228 with 10 home runs in 93 games last year in his first full season with Seattle.
He played for Detroit in 2010 and at the start of 2011 before being traded to the Mariners in a midseason deal that sent right-hander Doug Fister to the Tigers.