Hjerpe was placed on the 7-day injured list at Double-A Springfield on July 9 with an undisclosed injury.
He exited his July 2 start after two scoreless innings (39 pitches) having struck out three while allowing two hits and one walk, so he may have suffered the injury in that outing. Hjerpe has 17 strikeouts over 12 scoreless frames across his three most recent starts at Double-A after giving up five earned runs in 2.2 frames in his first start after getting promoted from High-A Peoria.