Diamond, a native of Guelph, Ontario, made his second career start on his native soil, and it was not a memorable one. He went just 4 2/3 innings, giving up six runs on eight hits while tying a career high with four walks.
"It's frustrating the way it all played out again," said Diamond, who fell to 5-8 with a 5.52 ERA after posting a 3.54 ERA as a rookie last season. "I'm really struggling keeping guys in the park."
Diamond has now served up 15 homers in 16 starts after giving up 17 long balls in 27 outings last year. But Twins manager Ron Gardenhire said he would stick with Diamond in the rotation for now.
"He'll be out there next time unless somebody tells me different," Gardenhire said.
Diamond got through the first three innings before giving up a two-run blast to Colby Rasmus in the fourth. Rasmus' blast came on a 3-2 curveball and scored Rajai Davis, who had doubled with two outs.
"I was pretty much trying to stay away," Rasmus said. "Look for that breaking ball away. I was able to foul off those heaters at the end. And he just left another one up out over the middle, and thankfully I got a hold of it."
The Twins came back to tie it in the top of the fifth on a two-run shot from rookie Aaron Hicks off right-hander Todd Redmond, who was making his second career start and first this season. The homer was the first hit of the game for the Twins, who were held hitless through the first 4 1/3 innings.
But Toronto retook the lead in a hurry, scoring four times in the bottom of the fifth. Jose Reyes led off the inning with a solo homer to left before Davis crushed a three-run blast to put the Blue Jays up by a comfortable margin.
"I feel like the only pitch I didn't execute today was the changeup to Reyes," Diamond said. "I left that ball up in the zone. I paid the price for that one. But I can't hang my head about the one to Rasmus or the one to Rajai Davis. I thought I saw him leaning out after the first pitch I threw, and so I tried to go up and in, and so I thought it was a pretty good pitch."
Diamond remained in the game after Davis' homer but walked Rasmus and was removed for reliever Anthony Swarzak. Swarzak was able to get out of the inning but ran into trouble in the sixth, as he served up an RBI double to Adam Lind with two outs.
Minnesota had already scored in the sixth against reliever Aaron Loup, but it was aided by a close call at first base, as Chris Parmelee hit into what appeared to be an inning-ending double play with the bases loaded. He was ruled safe by first-base umpire Dan Iassogna. But it was all the Twins could muster, as Clete Thomas grounded out to third to end the potential rally.
The Blue Jays tacked on four more runs in the seventh, with two being charged to right-hander Josh Roenicke and the others to left-hander Brian Duensing.
"To me, it looked like everyone we brought in left the ball up," Gardenhire said. "We talked about getting the ball down and keeping the ball on the infield, but everything was up. They made us pay today. They had some really great at-bats."
Trevor Plouffe capped the scoring for Minnesota with a two-run homer off reliever Brett Cecil with one out in the eighth inning. But it was not nearly enough for the Twins, who have now lost seven of eight and have not won a series of three games or more on the road since early May in Boston.
"Obviously, we want to play well, and guys are playing hard, but it's just not a great start to the road trip," Twins catcher Joe Mauer said. "Hopefully we can turn things around in Tampa. It's important to win series, and we haven't done that in a little while on the road. So we need to keep working and get after it and try to go down there and win a series against a pretty good Tampa team."