Lopez spent parts of three seasons with the Orioles, from 2020 to 2022, and made an All-Star appearance in that final campaign. He was traded to the Minnesota Twins on Aug. 2, 2022, in a deal involving right-hander Yennier Cano and others, then was shipped to Miami on July 26 for right-hander Dylan Floro.
Lopez, 30, is 6-2 with a 6.13 ERA and three saves in 49 relief appearances this season with the Twins and Marlins.
For his eight-year career, he is 22-40 with a 5.52 ERA and 27 saves in 218 games (58 starts). Lopez has played for the Milwaukee Brewers (2015-18), Kansas City Royals (2018-20), Orioles, Twins (2022-23) and Marlins (2023).
Also on Saturday, Baltimore designated right-hander Logan Gillaspie for assignment.
Gillaspie, 26, is 0-1 with a 6.00 ERA in 11 relief appearances this season. He is 1-1 with a 4.10 ERA in 28 career relief appearances with the Orioles.