McKirahan rejoins the Braves following a rehab assignment with Gwinnett. His suspension followed a positive test for the banned substance Ipamorelin, which releases growth hormone. He is active for Monday night's game against the Dodgers.
McKirahan allowed two runs in three appearances with Atlanta in April before the suspension. He was acquired off waivers from the Miami Marlins on April 1.
Kelly had a 6.75 ERA in three games covering two stints with Atlanta.