J.A Happ was outpitched by James Shields in his return to Toronto's starting rotation.
Shields threw eight strong innings, Evan Longoria drove in a run in his return from an injury, and the Tampa Bay Rays beat the Blue Jays 4-1 on Tuesday night.
Happ (0-1), making his first start with the Blue Jays, gave up four runs and seven hits in 4 1-3 innings.
He had made four relief appearances since being acquired from Houston on July 20.
"The result is the only thing that matters, but I did feel better than, probably, the numbers indicate," Happ said. "I felt like I was making some good pitches.
They used the whole field and they were falling for them, and weren't falling for us. A frustrating one."
Happ's previous start, while with the Astros, came on July 16. The left-hander threw 6 1-3 innings in a 2-0 win over San Diego.
"I got upwards of 80 pitches in, and hopefully we'll keep moving from there," Happ said.
Happ had five strikeouts and one walk.
"They didn't square up too many balls," Blue Jays manager John Farrell said. "First time out, we're not going to jump to any conclusions or judgments, certainly. This is an established major league pitcher."
Blue Jays rookie Chad Jenkins, who had his contract purchased from Double-A New Hampshire on Sunday, worked three shutout innings in his major league debut.
"He came in and threw the ball over the plate," Farrell said. "Had good sink to his fastballs. Showed a good slider as well. And didn't show any fear of contact. It was encouraging to see that kind of aggressiveness."
Colby Rasmus hit his 20th homer, a solo shot in the fourth, that got Toronto within 3-1.
Orioles 8, Mariners 7
BALTIMORE - Adam Jones singled home the winning run in the 14th inning, and the Baltimore Orioles beat the Seattle Mariners 8-7 Tuesday night after rallying from a five-run deficit.
It was the fourth straight victory for the Orioles, who moved eight games over .500 (59-51).
Matt Wieters homered twice, J.J. Hardy contributed a pivotal three-run drive and Nick Markakis had four hits for the Orioles.
