The right-hander, who relieved lefty Jon Lester after seven innings, started off the eighth but was removed before recording an out.
Bard allowed a ground-rule double to Brett Lawrie, an RBI single to Colby Rasmus and then proceeded to issue a four-pitch walk to J.P. Arencibia to put runners on first and second with none out.
That marked the end of Bard's day, as he was removed for Andrew Miller, who allowed an inherited run to score.
"It was just real quick. A close ball down the line, tailed in a little, jam shot and then the next four pitches, looked like it got away from him a little," manager Bobby Valentine said about Bard's outing.
The 27-year-old Bard was charged with two earned runs and has now allowed at least one run in each of his four appearances since rejoining the Red Sox at the end of August.
Bard, once known as a flamethrower, did not throw a pitch above 93 mph on Sunday in his first appearance since Sept. 7.
With rosters being expanded, coupled with Bard's inconsistencies, Valentine hasn't turned to him recently, something Bard admitted has required an adjustment.
"I felt all right, it's just a challenge pitching not getting into a game for seven days, which is part of being in an 11-man bullpen in September," Bard said. "It's just kind of how it goes sometimes. I'm just going to have to get better at it, I guess.
"It's nobody's fault. It's just part of being, you have a lot guys out there that need to throw and guys who have established roles, so kind of getting me in there when they can. It's frustrating to come out and do that after sitting for a week, but I went out there trying. It just didn't happen how I planned."
Bard said he understood Valentine's decision to remove him but wanted to stay out there and clean up the mess he created.
"I definitely see what he's doing, it makes perfect sense," Bard said. "When I'm out there, I want the ball, I want to stay in there and get out of my own jam."
Bard said it has been difficult to stay ready because he has no idea how often he will be used. Every couple days he has been throwing 10-15 pitch bullpen sessions to try to stay sharp.
"You don't want to overdo it, because there is a good chance you will be in there, but at the same time, you have to do something to kind of simulate being off the mound," Bard said.
Bard returned to the Red Sox after spending more than two months in the Minors at Triple-A Pawtucket.
Following three seasons as a member in Boston's bullpen, where he was a key piece, Bard began the 2012 season in the rotation for the first time in his big league career, but it didn't work out well.
He was sent down after going 5-6 with a 5.24 ERA over 10 starts and 11 appearances. He allowed five runs in four separate starts, including an outing against Toronto on June 3, in what would eventually be his last start in the rotation. In that outing, also at Rogers Centre, Bard lasted just 1 2/3 innings, walked six and hit two batters. Bard said he had no memories of that performance Sunday and doesn't consider Toronto to be any more difficult of a place to pitch than other parks around the league.
With Pawtucket, Bard didn't get any better, going 3-2 with a 7.03 ERA over 31 games, all but one of which were as a reliever. He walked 29 over his 32 innings of work.
Although he continues to struggle and isn't being turned to often, Valentine said he will keep going to Bard down the final stretch of the season.
"He will have some more opportunities to get it right," Valentine said.
Chris Toman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.