Career
He made his Major League Baseball (MLB) debut with the Braves in 2015. Cunniff was drafted by the Florida Marlins in the 27th round of the 2010 Major League Baseball Draft out of California State University San Bernardino. He pitched in the Marlins organization for one year, making 18 appearances before being released.
From 2011 to 2013 he played in the Frontier League, with the River City Rascals.
Cunniff signed with the Atlanta Braves in June 2013. He compiled a 1.99 European Research Area in 20 appearances at Class–A Lynchburg.
The next year, Cunniff made nine more appearances with Lynchburg until a promotion to the Southern League"s Mississippi Braves. At the Double–A level, Cunniff pitched in 33 games, recording a 2.05 European Research Area. The Braves added Cunniff to the team"s 40-man roster on November 19, 2014.
He was invited to spring training in 2015, and sent to the minors as one of the final cuts.
After Craig Kimbrel and Melvin Upton, Junior. were traded to the San Diego Padres on April 6, Cunniff was called up. Cunniff went on the disabled list for the first time in his career on June 26, 2015, after suffering a groin strain. He was designated for assignment on December 18, 2015.