Estevez (foot) was removed from his rehab appearance at Triple-A Omaha on Wednesday due to shoulder discomfort, Anne Rogers of MLB.com reports.
Estevez's velocity was down during his appearance Wednesday, and he managed to record just two outs before leaving the game alongside a trainer. The right-hander has been on the injured list since the beginning of April due to a left foot injury and was trending toward returning to Kansas City's bullpen around mid-May. However, his latest setback could extend his time on the IL and Lucas Erceg's run as the Royals' primary closer.