The Blue Jays selected the contract of Castillo on Saturday, baseball analyst Alfonso E. Saer Gomez reports.
He has a 1.92 ERA, 0.98 WHIP and 64 strikeouts in 56.1 innings split evenly between Double-A and Triple-A. Castillo has been working as a starter in the minors, and the Jays have a full five-man rotation, so it's unclear if Castillo will be used in long relief or if he will get a chance to make a spot start.