Stephen was placed on the 7-day minor-league injured list at Double-A Akron on Wednesday with right elbow soreness, Tim Stebbins of MLB.com reports.
Stephen last pitched Sunday for Akron, throwing just one scoreless inning before exiting the game. He's in the midst of his first full season in the organization after he was acquired from the Blue Jays last season at the trade deadline as the return for Shane Bieber. Stephen has logged a 3.44 ERA and 1.36 WHIP with 49 strikeouts and 23 walks over 12 starts (55 IP) for the RubberDucks.