Catcher Erik Kratz was optioned to Buffalo and right-hander Sergio Santos was placed on the 15-day disabled list with a sore elbow, retroactive to May 10.
Santos, who lost his job as closer after blowing back-to-back save chances earlier this season, is 0-2 with a 9.00 ERA and five saves in 14 appearances.
Acquired from the Chicago White Sox following the 2011 season, Santos was limited to six games in 2012 before undergoing shoulder surgery. His 2013 season was cut short by elbow surgery after 29 games.
Jenkins has made three relief appearances for the Blue Jays this season. He has no record and a 9.00 ERA. Diaz, who can also play the outfield, has played in 22 games for the Blue Jays, batting .176 with no homers and four RBIs.
Kratz was batting .231 with two homers and six RBIs in 11 games.