Hernandez was designated for assignment by the Astros on Saturday, Chandler Rome of The Athletic reports.
Hernandez was dropped from the 40-man roster to make room for Lance McCullers on the major-league roster after McCullers was activated from the 15-day injured list Saturday. Hernandez made five appearances with Houston after being called up from Triple-A Sugar Land on Sept. 10, surrendering two runs on four hits and three walks, while striking out four over four innings.