Pittsburgh selected Mlodzinski's contract from Triple-A Indianapolis on Friday.
Drafted by the Pirates with the No. 31 overall pick in 2020, Mlodzinski moved exclusively into a relief role this year with Indianapolis and it has allowed him to make a quicker ascent to the majors. The 24-year-old right-hander had a 3.16 ERA with 31 strikeouts through 25.2 innings this season at the Triple-A level.