Castillo (hand) has given up three earned runs on five hits and no walks while striking out two batters over 2.2 innings in three appearances since being reinstated from Triple-A Reno's 7-day injured list July 19.
Castillo opened the season on Reno's IL after suffering a hand injury in spring training. He began a rehab assignment in the rookie-level Arizona Complex League in late May, but he was pulled off the assignment after just one appearance. It's unclear if Castillo experienced a setback with the hand injury or was contending with a new injury, but he was cleared to resume the rehab assignment six weeks later before he finally got the green light to join the Triple-A club. Castillo has previously made 40 relief appearances at the big-league level from 2018 through 2023, but he looks to be a long ways away from getting a look in the Arizona bullpen.