Hernandez was optioned to Triple-A Sugar Land on Sunday, Chandler Rome of The Athletic reports.
No corresponding move was announced, but the Astros are expected to have a fresh arm in the clubhouse soon to replace Hernandez in the bullpen. Hernandez worked 3.2 innings in relief of Spencer Arrighetti on Saturday, allowing just one run on three hits while striking out five. He should get another big-league opportunity before long.