Hernandez was designated for assignment by the Mariners on Thursday.
Hernandez appeared in three games with the Mariners after being claimed off waivers and added to the major-league roster Aug. 3, giving up three runs on two hits and two walks while striking out three batters over 2.1 innings. He will now once again be placed on waivers, and if he goes unclaimed, he'll either report to Triple-A Tacoma or be released outright. Eduard Bazardo was recalled from Triple-A in a corresponding move, replacing Hernandez in the major-league bullpen.