The Indians’ Justin Masterson threw seven shutout innings while allowing three hits and striking out 11.
Hernandez came into the game with the American League’s lowest ERA at 1.53, but gave up eight hits and six runs in a season-low five innings.
Hernandez was pulled an inning early in his last start in New York when his back tightened up, but both he and manager Eric Wedge said that wasn’t an issue in this game.
The three-time All-Star had allowed just five runs (four earned) over 44 innings in his prior six outings. Hernandez fell to 5-3, and his ERA now stands at 2.07.
After coming to Cleveland having won 11 of their previous 17 games, the Mariners have now dropped back to third behind the A’s at 20-24.