Toronto also didn't offer a contract to right-hander Jason Adam, who was not eligible for arbitration.
Bass was 2-4 with a 3.56 ERA in 44 relief appearances for Seattle last season, then was claimed off waivers by Toronto on Oct. 29. A veteran of eight major league seasons, he also has pitched for San Diego (2011-13), Texas (2015) and the Chicago Cubs (2018). He spent 2016 in Japan with the Pacific League's Hokkaido Nippon-Ham Fighters.
Toronto also agreed to minor league contracts with Canadian right-hander Phillippe Aumont along with right-handers A.J. Cole and Justin Miller, second baseman Andy Burns and outfielder Patrick Kivlehan. They will all report to major league spring training.