Medlen was 0-1 with a 15.75 ERA in one start (against the Houston Astros) for the Diamondbacks this season. He also struggled in the minors, going 0-5 with a 5.03 ERA in seven starts for Triple-A Reno.
Medlen underwent two Tommy John procedures (in 2010 and '14) during his career.
His best seasons came in 2012 and '13 for the Atlanta Braves. In 2012 he went 10-1 with a save in 50 appearances, including 12 starts. He started 31 games in 2013 and won a career-best 15 games, finishing 15-12 with a 3.11 ERA.
He finishes his major league career with a 41-26 record and 3.33 ERA in eight seasons with the Braves, Kansas City Royals and Diamondbacks.