KANSAS CITY, Mo. -- After ending April with nine consecutive defeats and an American League worst record of 10-20 on May 7, postseason play was only a mirage for the Kansas City Royals.

That is no longer the case. Kansas City is an American League-best 15-6 in June.

The Royals are going for their 12th victory in 14 games Sunday when they try to sweep the Toronto Blue Jays. The recent surge has moved Kansas City (37-36) above .500 for the first time this year and thinking the big picture, which includes October play.

"I don't know if there's a boost," Royals manager Ned Yost said of reaching .500. "It was a definite goal for us. We had to get back to .500 before we could get to the point and start really focusing on competing.

"(Reaching) .500 was an important milestone and now we've battled back and we've got there. Now the goal is to get past it. You've got to continue play good and get past .500. Your quest is to compete for this division, which we're right in the middle of it, and compete for a wild card."

Left-hander Jason Vargas picked up his major league-leading 11th victory Saturday as the Royals nipped the Blue Jays 3-2.

"Hopefully we just keep stringing them together and keep pushing ourselves further and further over that mark," Vargas said.

The Blue Jays (35-39) were within a game of .500 after winning Wednesday at Texas, but they have since lost three in a row.

"That's the frustrating part of this," Toronto manager John Gibbons said. "We need to pick it up; you know right now we're going a little bit backwards. We climbed close. We don't want to go that other direction. We need to pick it up."

After the game Sunday, the Blue Jays return home Tuesday and play 10 of their next 13 games at the Rogers Centre before the four-day All-Star break.

"Bottom line, try to win a game tomorrow and go back home," shortstop Troy Tulowitzki said. "I think we have only one road series before the All-Star break. Play good at home and get ourselves back into this thing."

The Royals will start right-hander Jason Hammel, who has won his past three decisions. He held the Boston Red Sox to two runs over seven innings in a 4-2 victory Monday.

Hammel is 3-1 with a 3.35 ERA in his past six starts after beginning the season 1-5 with a 6.20 ERA.

Hammel will be facing the Blue Jays for the 16th time in his career and making his 12th start. He is 4-2 with a 4.57 ERA against them. Hammel, however, has not pitched against Toronto since 2013, when he was with the Baltimore Orioles.

The Blue Jays will turn to left-hander Francisco Liriano, who has only two quality starts in 11 appearances. He is 3-3 with a 5.76 ERA, striking out 52 in 50 innings and walking 30, while allowing 32 earned runs and 53 hits.

Liriano is 6-5 with a 4.45 ERA in 18 career appearances, including 15 starts, against the Royals.

Alex Gordon has eight hits in 29 at-bats (.276) against Liriano, while Alcides Escobar is 2-for-18 and Eric Hosmer is 2-for-12. No other current Royal has more than 10 at-bats versus Liriano. Salvador Perez is 3-for-7 with a home run and Lorenzo Cain is 2-for-6 with a homer.

The two teams will not see each other again until Sept. 19, the start of a three-game series in Toronto.