Along with needing to rest Cunniff, the Braves had a need to add a reliever who has the ability to work more than two innings. David Aardsma will be unavailable until at least Sunday because he threw three innings during Thursday's loss to the Nationals.
The Braves opted to make this transaction when they examined Cunniff after he surrendered an unearned run and two hits in one inning on Thursday. This was just the fourth appearance the rookie reliever made since his groin started bothering him during a June 11 appearance against the Padres.
Cunniff has produced a 4.23 ERA in the 30 appearances he has made dating back to his April 7 debut. Though he would be eligible to be activated on July 11, the Braves might opt to give him a chance to rest through the All-Star break, which begins two days later.
Marimon has surrendered 12 hits, issued four walks and allowed eight earned runs in the 8 1/3 innings he has compiled during his two previous stints with Atlanta this year. The Braves will likely only use him during lopsided games or in emergency situations.
Mark Bowman is a reporter for MLB.com. Listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.