Happ made his first start since May 7, when he suffered a skull fracture and a sprained right knee after being struck behind the left ear by a line drive from Tampa Bay's Desmond Jennings. Happ left the field on a stretcher, spent the night in the hospital and had three months of rehabilitation, primarily for the knee.
Presented with a 7-2 lead by the third inning, Happ couldn't deny the fifth-inning rally, leaving with the bases loaded and no outs.
Brandon Maurer (3-7), who allowed eight baserunners and no runs in 3 1-3 innings, earned the win.
Happ's day ended when he walked Michael Morse. He was charged with seven runs and seven hits, walking two and striking out three in his 99-pitch outing.
Aaron Loup (4-4) took over allowed one run on Michael Saunders' forceout, two on Justin Smoak's double and two on Quintero's home run over the left-field wall, his second. He also had an RBI in the fourth.
Danny Farquhar worked an inning for his third save in five chances.
Edwin Encarnacion and Adam Lind hit back-to-back home runs for the Jays in the third, their 30th and 14th, respectively. It is Encarnacion's second straight 30-homer season.
Aaron Harang went just two-plus innings, allowing seven runs and five hits. He walked three and all scored.
It was the shortest outing for Harang this season. The last time he worked just two innings was Oct. 3, 2010, with Cincinnati against Milwaukee. He has had two career one-inning outings.
It's the fourth time he has allowed seven runs, including his previous start, a 10-5 loss to Baltimore.
The Mariners touched Happ for two runs in the first. Leadoff batter Brad Miller dribbled a single up the third-base line. Nick Franklin followed with a RBI triple into the right-center gap. That broke his 0-for-27 hitless drought.
Franklin came home on Kyle Seager's right-side groundout.
The Blue Jays scored five runs in the second. Encarnacion and Lind worked walks, and Brett Lawrie singled through the right side, scoring Encarnacion and sending Lind to third.
Lawrie, born in nearby Langley, British Columbia, was 6 for 11 in the series and reached base eight times with a pair of RBIs.
Harang walked Mark DeRosa to load the bases. Josh Thole, rushed into the starting role minutes before game time because catcher J.P. Arencibia was scratched with right knee soreness, had a two-run double into the left-field seats.
Thole reached third on a right-side groundout and Emilio Bonifacio sent him home with a left-side bunt single.
There were 14 walks issued by both teams, including a season-high nine by the Mariners staff.
NOTES: Mariners manager Eric Wedge paid a visit to the clubhouse before the game. He has missed the past 16 games after suffering a stroke July 22. He said he is still undergoing tests to get to full recovery and be able to handle the rigors of the job. He's anxious to get back but there is no timetable for his return. . Both teams have an off day Thursday. Mariners acting manager Robby Thompson plans to skip Erasmo Ramirez's start Friday to maintain a five-day routine for his other starters. Blue Jays manager John Gibbons plans to keep all five of his starters on the same rotation. "These guys could all use the (extra) day," he said. . Tests on Jays' RHP Steve Delabar, placed on the 15-day DL Sunday, revealed inflammation in his right shoulder. Nothing serious, Gibbons said. . Plate umpire Dale Scott was hit hard on his face mask by Jose Bautista's foul ball in the second. He remained in the game for one inning before leaving. Todd Tichenor rotated from first in the third inning to replace him behind the plate.