Heuer had his contract selected from Triple-A Charlotte on Thursday, James Fegan of The Athletic reports.
Heuer will get his first taste of the majors in 2020 after spending most of 2019 with Double-A Birmingham, finishing with a 1.84 ERA and 1.09 WHIP across 29.1 innings (22 appearances). Given his lack of prior big-league experience, he'll likely be tasked with lower-leverage work.