Castillo (elbow) was placed on the 60-day injured list Saturday.
Castillo's placement on the injured list is simply procedural since he was recently diagnosed with a UCL tear that will require Tommy John surgery. As a result, he'll miss the entire 2021 campaign and could also be sidelined to begin 2022. The move will clear a spot on the 40-man roster for right-hander Jordan Humphreys, who was claimed off waivers in a corresponding move.