Wallach went 2-for-3 with a walk, a double, a run scored and an RBI in Sunday's 6-0 win over the Cubs.
The 26-year-old catcher had a brutal start to the season, going 0-for-10 with eight strikeouts in his first two games, but Marlins manager Don Mattingly stuck with him and got rewarded for his patience Sunday. Wallach appears set to see regular duty behind the plate until J.T. Realmuto (back) is ready to come off the disabled list in a couple of weeks.