The Baltimore Orioles earned a 3-1 victory over the Toronto Blue Jays at Rogers Centre as Buehrle lasted five innings, bringing his total to 194 1-3 for the season.
"Obviously with five innings I wasn't very pleased with myself," he said. "I got out of some big jams and kind of gave us a chance there for a bit."
After going through a stretch of nine starts in which he was 6-0, Buehrle (11-9) has lost his past two starts.
Buehrle allowed six hits, three walks and three runs (two earned), an improvement from his last start in which he gave up 12 hits and eight runs in against the Los Angeles Angels.
A two-run double by Danny Valencia in the third and a bases-loaded walk to Chris Davis in the fourth were the keys to his loss.
"It was a battle for him today," Blue Jays manager John Gibbons said. "But he has that knack of hanging around and surviving and keeping you in the game. It's been a long year for him. He kept the game in check without his best stuff."
Adam Lind homered for the Blue Jays as they picked up their fifth loss of their last six games.
The Orioles (79-70), who entered Sunday 3 1-2 games removed from an American League wild card spot won two of three from the Blue Jays (68-81) to take the three-game series.
Orioles right-hander Miguel Gonzalez (10-7) was removed from the game after 5 1-3 innings after a visit by manager Buck Showalter and a trainer. He had just struck out Lind to open the sixth and the club reported that it he suffered a right groin strain.
Gonzalez held the Blue Jays to one run on six hits to pick up the win and give him a career high.
"I think we'll have a better idea tomorrow or the next day," Orioles manager Buck Showalter said of the extent of the injury to Gonzalez. "He said he felt it two pitches before."
Jim Johnson pitched the ninth for his 45th save, despite giving up a leadoff single to Anthony Gose.
Buehrle could not pinpoint the reason for his recent struggles.
"I'm not the top workout guy but I get back there and do enough stuff to try to finish strong and go deep into games late in the season," he said. "I don't know if it's getting a little worn out. The last couple of outings haven't been too good.
"My pitch count was getting high and it's not allowing me to go deep into games. I just need to make better pitches and get early contact."
Lind led off the bottom of the second with his 21st homer of the season to open the scoring.
Valencia doubled in two runs with two out in the third to put the Orioles into a 2-1 lead. The double scored Nick Markakis, who led off the inning with a single and Adam Jones, who walked with two out.
"Any time you get a hit with runners in scoring position it's huge, especially with two outs," Valencia said. "My at-bat before that, I left two on in the same situation, so it was nice to come through and get those runs."
The Orioles added a run in the fourth to go ahead 3-1 when Chris Davis walked with the bases loaded. He forced in Michael Morse who reached first on an error when shortstop Jose Reyes dropped his line drive.
Morse took third on a double by Brian Roberts. After Davis walked, Blue Jays second baseman Ryan Goins ended the inning on a diving play on a ground ball by Jones.
"There were a couple of close calls (on balls and strikes ), balls were finding the holes," Buehrle said. "When you're going good those things find your position guys, you're getting strikes called or getting close pitches. It's going your way.
"I've got to do a better job of not walking a guy with the bases loaded. At the same time you know what Chris Davis can do and you don't want to give in to him, a walk is better than a home run. Overall it wasn't the best today but it was alright."
The Blue Jays threatened to cut into the lead in the seventh. Edwin Encarnacion hit a ground-rule double against Francisco Rodriguez and Brett Lawrie, who had singled with two out had to stop at third. After Lind was intentionally walked, Tommy Hunter replaced Rodriguez and struck out Moises Sierra to end the threat.
"They got out of some jams," Gibbons said. "They're a good ball club, they're right in the thick of it. They don't throw a bunch of pitchers at you that can overpower you but they can all pitch.
"They all have the ability to make a key pitch at the right time ... we got our hits but just couldn't get that big one."
Notes: Attendance at Rogers Centre was 22,331. ... After hitting a home run in each of his first two games back from the disabled list, Blue Jays CF Colby Rasmus was given the day off because of what the club termed "overall soreness". ... Orioles SS J.J. Hardy was 0-for-4 to end a seven-game hit streak. ... The Blue Jays have Monday off before facing the New York Yankees in a three-game series at Rogers Centre on Tuesday. RHP R.A. Dickey (12-12, 4.38 earned-run average) will start the opener for the Blue Jays with LHP Andy Pettitte (10-9, 4.04 ERA) starting for the Yankees.