Keller (0-1) gave up four runs on six hits and two walks while striking out four in four innings in Saturday's 6-2 loss in St. Louis.
Keller allowed a run in the first and three runs in the third, including a Paul DeJong two-run home run. The 26-year-old had a strong spring with a 2.92 ERA in four starts but struggled in his 2022 debut. While Keller has thrived in the minor leagues, he has yet to find his way for the Pirates outside of five good starts in 2020. His next start will likely be at home against Washington at the end of next week.