Blanco played in 21 games for the D-backs last season and batted .188 with one home run and seven RBIs.
His year ended in early August due to a torn ligament in his left thumb, and the D-backs declined his option following the season.
The 41-year-old veteran has appeared in 921 games over 15 big league seasons with the Dodgers, Rockies, Brewers, Braves, Twins, Cubs, Padres, Mets and Arizona, compiling a lifetime .227 batting average.
Blanco also has some history with the Blue Jays' new ace, knuckleballer R.A. Dickey, when both were with the Mets in 2010. Pitching to Blanco, Dickey compiled a 2.52 ERA over 50 innings in seven games.
To make room on Toronto's 40-man roster, left-hander Tommy Hottovy was designated for assignment.
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.