The Pittsburgh Pirates hope that Francisco Liriano can play the role of stopper on Monday night in the opener of a three-game series versus the San Diego Padres.

Liriano has been excellent in his first season with the Pirates, going 13-5 with a 2.68 earned run average over 18 starts. He showed an ability to bounce back last time out as he followed up his worst start of the season with one of his best.

The left-hander was drilled for 10 runs and 12 hits in a loss at Colorado on Aug. 9, but rebounded to throw a complete game to beat St. Louis on Wednesday. Liriano gave up a run, four hits and a walk in a 5-1 win, striking out six during his second complete game of the season.

"He attacked them and stayed aggressive," Pirates manager Clint Hurdle said.

Liriano, 29, has faced the Padres only once before and that came back in 2011 with Minnesota. He got a no-decision in that outing, allowing three runs over seven innings and striking out eight.

The Pirates are coming off a series loss to Arizona, dropping the final two games of the series and falling in defeat 4-2 in 16 innings on Sunday. The Diamondbacks plated the winning runs on Adam Eaton's two-run double with two out in the top of the frame.

Kris Johnson, called up by the Pirates from Triple-A Indianapolis prior to the contest, held Arizona scoreless for five consecutive innings of relief in his Major League debut, but wound up the loser after being touched for both runs in the 16th.

"It's a little nerve racking at first," Johnson said of his debut. "I just tried to go as deep as I could to try and save the bullpen. That was the main thing and then try to keep the team in the ballgame and hopefully we could score some runs at the end."

Jordy Mercer went 3-for-5 with an RBI double for Pittsburgh, which has lost seven of its past nine and saw its edge for first place in the NL Central over St. Louis shaved to just a game.

Liriano and the Pirates will need to cool off Will Venable, who has logged a career-high 15-game hitting streak for the Padres. He is batting .377 with five homers over that streak and notched the game-winning homer in the ninth inning of Sunday's 4-3 victory over the New York Mets.

Venable, who had four hits in Saturday's victory, snuck his solo homer just inside the foul pole in right field for his 17th homer of the year.

"He's really playing the game hard and you get rewarded for playing the game hard," said Padres manager Bud Black. "He's swinging the bat great."

Chris Denorfia delivered a game-tying RBI in the eighth for the Padres, who have won their last two to split the four-game series.

Getting the call for the Padres tonight is Andrew Cashner, who has lost back- to-back starts since winning three in a row but pitched well last time out.

The 26-year-old righty dropped a 4-2 decision in Colorado on Wednesday, yielding three runs over seven innings. He gave up six hits but did not walk a batter while striking out seven and retired the final 14 batters faced.

"I thought I made some really good pitches today," said Cashner. "I just thought that some balls fell in. A couple of different plays and it's a different ballgame."

Cashner is 8-7 with a 3.87 ERA in 25 games this season, including 20 starts. He'll make his first career start versus the Pirates, having gone 0-2 with a 3.00 ERA in four previous relief appearances against them.

The Padres have won 18 of their past 21 meetings with the Pirates and won all three encounters at home in this series last year.