The Red Sox further bolstered their pitching depth on Tuesday, claiming right-hander Max Castillo off waivers from the Kansas City Royals.

The 24-year-old Castillo has appeared in 21 big league games, including seven with the Royals in 2023, and has posted a 5.43 career ERA over those outings. Last season he also made 22 appearances (21 starts) at Triple-A, posting a 4.58 ERA over 116 innings pitched.

Currently Castillo is playing winter ball in Venezuela, and as of Tuesday afternoon he has gone 5-0 with a 2.72 ERA in 49.2 innings for Cardenales de Lara.

Originally signed as an international free agent by the Toronto Blue Jays in 2015, Castillo debuted for the Blue Jays in 2022 before heading to Kansas City as part of the Whit Merrifield trade. With Boston he projects as a depth arm who will have a chance to compete for a spot at the back end of the bullpen and who could move back and forth between the majors and Triple-A as needed.

Boston’s 40-man roster is now at 40.