Rauch, who gave up the game-winning eighth-inning home run in the Jays' 6-5 loss to the Seattle Mariners on Monday night, was placed on the 15-day disabled list. He was 5-4 with a 11 saves and a 4.47 ERA in a staff-high 51 appearances.
The club also designated left-handed reliever Trever Miller for assignment. He gave up the game-tying home run in the eighth. Miller came to the Blue Jays on July 27 in an eight-player trade with the St. Louis Cardinals.
Ledezma is making his second stint with the big club this season. He appeared in two games with a 9.00 ERA. He was 1-1 with a 4.50 ERA and four saves in 36 games with Las Vegas.
Lewis, coming back to his hometown of Seattle, was 3-3 with a 6.60 ERA and four saves in 42 games for Vegas. He had 14 appearances for the Jays last season, going 0-0 with a 6.75 ERA.