The Pittsburgh Pirates placed right-handed reliever Isaac Mattson on the 15-day injured list before Tuesday's game against the White Sox due to right hip inflammation. Manager Don Kelly said Mattson "needs some rest and rehab to clear up" his hip condition. The move was retroactive to Sept. 6.

Mattson has no record with a 5.35 ERA in 38 2/3 innings over 38 games this season, his fourth in the majors and third with the Pirates. The 31-year-old Mattson, a product of the University of Pittsburgh, last pitched on Saturday against the Los Angeles Angels, giving up three runs on four hits in a 6-1 loss. In a corresponding move, the Pirates recalled left-hander Brandon Eisert from Triple-A Indianapolis.

Eisert is 0-1 with a 6.23 ERA in nine games over 8 2/3 innings with the Pirates. He started the season with the White Sox, who traded him to Pittsburgh on July 11, along with infielder and 2023 first-round draft pick Jacob Gonzalez for left-hander Jaden Woods and future considerations. Eisert has a combined record this season of 2-2 with a 6.00 ERA over 36 innings in 34 games.