Castro's contract was purchased by the Giants on Friday.

A 21-year-old righty who logged a 2.66 ERA, 0.96 WHIP and 61:13 K:BB in 67.2 innings in short-season ball in 2019, Castro is multiple years away from the majors, but the Giants like his potential enough to protect him from the Rule 5 draft. He could open the year at Low-A or High-A.