Lopez (shoulder) will throw 25-to-30 pitches in a bullpen session Tuesday, Christina De Nicola of MLB.com reports.
The Marlins slowed Lopez's progression in late August after he made a three-inning rehab appearance Aug. 21, but he's now working toward building back up. It's not yet clear whether the right-hander will have enough time to rejoin the Marlins in 2021 with just under three weeks remaining in the regular season.