Hunter lasted just 4 1/3 innings, allowing five runs -- all earned -- on eight hits. He allowed four of those runs in the sixth inning, which included a game-tying grand slam by Will Middlebrooks, the third baseman's first big league homer.
Hunter's outing was just the third time in 13 games in which an Orioles starter has not thrown a quality start (six or more innings, three or fewer earned runs). It's also the earliest exit of an Orioles starter since the fourth game of the season, when Brian Matusz lasted just four innings against the Yankees on April 9.
The 25-year-old right-hander unraveled in the fifth up 5-1. He allowed back-to-back singles by David Ortiz and Cody Ross to open the inning and then walked catcher Jarrod Saltalamacchia to load the bases.
Middlebrooks then hit a first-pitch curveball that sailed over the Green Monster in left field, tying the game. Two batters later, Hunter was pulled from the game.
Luis Ayala was able to end the inning for the Orioles, induced two fly-ball outs to left.
Now in the bottom of the sixth, the Orioles and Red Sox are still tied at 5.