Left-hander Rob Rasmussen will be optioned to Triple-A Buffalo to make room for Tolleson on the 25-man roster. Rasmussen has a 3.18 ERA in 11 1/3 innings with the Blue Jays this season.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.