Mark Buehrle proved nearly unbeatable through the season's first couple months, but he hasn't seen anything go his way since.

Looking to avoid a fifth consecutive loss, Buehrle takes the mound Saturday (10:05 p.m. ET) opposite fellow all-star hopeful Scott Kazmir as the slumping Toronto Blue Jays continue a four-game road set against the Oakland Athletics a day after they pulled off a huge trade.

After opening 10-1 thanks in part to receiving an average of 6.75 runs of support, Buehrle (10-5, 2.50 earned-run average) has been backed by a combined nine runs during a five-start winless funk.

The left-hander, who has pitched to a 3.44 ERA while going 0-4 over that stretch, hasn't suffered five consecutive defeats since 2010 with the Chicago White Sox.

Buehrle threw eight innings of two-run ball in Sunday's 4-0 loss against his former team.

"You know what he has, it just seems like it's tough to line him up like you want to," White Sox first baseman Paul Konerko said of Buehrle.

Buehrle is 8-13 with a 3.63 ERA lifetime versus the A's, but he's won his last four starts against them behind a 3.16 ERA. Coco Crisp and Alberto Callaspo are both 3-for-21 against Buehrle since 2009.

Kazmir (9-3, 2.61) is part of an Oakland staff that boasts an AL-best 3.18 ERA, and the A's rotation just got better.

Oakland has an agreement in place to acquire right-handers Jeff Samardzija and Jason Hammel from the Chicago Cubs for three top prospects in a surprising trade for the team with the best record in the majors. They'll join a rotation that also includes Sonny Gray and Tommy Milone.

Kazmir shakes off injury

Kazmir, who is holding opponents to a .216 average to rank fifth in the American League, is good to go after appearing to injure himself before exiting Monday's 5-4 walkoff loss at Detroit with one out in the sixth inning.

"My calf just cramped up," said Kazmir, who allowed one run and struck out seven. "I was OK until I tried to push off."

Kazmir, who was tagged for a season-high seven runs over three innings in a 10-1 road loss to the New York Mets in his previous start June 24, has surrendered two runs or fewer in six of his last seven.

Kazmir gave up three runs over seven innings in a 3-2 loss at Toronto on May 23, his first appearance against the Blue Jays since 2010.

Toronto (47-41) is looking to break out after scoring one run through the first two in this series. The Blue Jays were shut out for the second time in five games, going 0-for-8 with runners in scoring position in Friday's 1-0, 12-inning defeat.

Leadoff hitter Jose Reyes is 7-for-33 with just one run during Toronto's 2-5 slide. The Blue Jays had won 18 of 21 before posting a 9-17 record since June 7.

"It's frustrating," manager John Gibbons said. "We need to start picking up some hits to win some ball games."

Oakland's Nick Punto entered the 12th mired in a 2-for-31 slump before connecting on what proved to be the game-winning double after Derek Norris scored from first on Melky Cabrera's fielding error. The A's are 20-7 at home since May 7, baseball's second-best record during that time.

"I'm sure [the fans] were ready to go home and get the barbecues started," Punto said.

While third baseman Josh Donaldson (back) returned to the lineup Friday, Brandon Moss was forced to exit due to a sprained left ankle. Moss leads the team with 19 homers and 62 runs batted in.

Left-fielder Yoenis Cespedes has three hits in his past 24 at-bats against the Blue Jays after going 0-for-8 over the last two days.