"With the DH these next two days, we needed an arm, a guy in the bullpen to help us out," Braves manager Fredi Gonzalez said.
The Braves squandered a five-run lead in Sunday's 10-8 loss to the Mets in large part because of the struggling bullpen, which combined to give up four runs over 3 2/3 innings. The unit entered Monday with the worst ERA (4.64) in the National League.
Needing starter Williams Perez to pitch one relief inning during an extra-innings win on Saturday also factored into the decision. Marimon's addition provided the Braves with added protection during Perez's start on Monday.
"[We're] throwing a kid today that had to save the game for us Saturday," Gonzalez said before the game.
Marimon made his Major League debut on April 14, when he allowed two runs over four relief innings against the Marlins, and he went on to post a 6.14 ERA in four appearances.
The 26-year-old Cunningham had been scuffling at the plate since earning a callup last month, hitting .239 with just four extra-base hits (all doubles) in 71 at-bats.
• Gonzalez said he is leaning toward using Chris Johnson as the DH against Boston lefty Wade Miley on Tuesday. Braves designated hitters went 4-for-9 in their only other Interleague road series this season (Toronto) after hitting a collective .189 at the position from 2012-14.
Alec Shirkey is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.