Diaz was optioned to Triple-A Syracuse on Friday.
Diaz has just a single big-league appearance on his resume, so he was never particularly likely to break camp on the active roster. That outing, in which he walked four of the seven batters he faced and allowed two runs as a Blue Jay back in 2019, was his only one above Double-A, so he'll need to prove himself at the Triple-A level before pushing to return to the highest level.