The Blue Jays made the move Monday. Toronto is playing in the AL Championship Series, but Venditte is not eligible.
The 30-year-old Venditte made his major league debut this season, throwing as a left-hander and as a righty. The ambidextrous pitcher was 2-2 with a 4.40 ERA in 26 games.
Toronto also said infielder Darwin Barney was designated for assignment.
In another move, Oakland righty Cody Martin was claimed off waivers by Seattle. He made his big league debut this year and was 2-5 with a 7.92 ERA in 25 games for Atlanta and the A's.