Villalobos was claimed off waivers by the Pirates on Tuesday and optioned to Triple-A Indianapolis.
Villalobos had been designated for assignment Sunday by the Marlins. The 25-year-old right-hander was off to an ugly start this season at Triple-A Jacksonville, but he posted a 2.86 ERA and 101:29 K:BB over 78.2 innings of relief between the Double-A and Triple-A levels in 2022.