Shafer's contract was purchased by the Blue Jays on Tuesday.
Shafer recorded a 3.24 ERA in 8.1 innings in his debut season for the Blue Jays last year, but that figure obscures a 2:7 K:BB and a 7.12 FIP. In 18.2 frames for Triple-A Buffalo this year, he owns an excellent 0.96 ERA. Zac Rosscup was designated for assignment in a corresponding move.