Miller (elbow) will undergo Tommy John surgery to repair the torn UCL in his right arm, Tommy Stokke of FanRag Sports reports.
Miller made his decision after meeting with multiple doctors, though his transfer to the 60-day DL effectively foreshadowed an end to his 2017 season. The 26-year-old was trying to improve upon his dismal 2016 showing, when he posted a 6.15 ERA and a 1.67 WHIP over 20 games in his debut season with Arizona. Instead, he'll undergo the dreaded procedure, which will keep him out 12-18 months, meaning he'll be in line for a return late next season, if that. The D-Backs, meanwhile, will have to move on with Zack Godley or another replacement in the rotation.