Updated

The Pittsburgh Pirates fell behind in the race for the National League Central lead and are winless so far in their four-game series with the San Diego Padres at PNC Park.

The Pirates hope to keep pace with the St. Louis Cardinals in the division Wednesday, when they resume this set versus San Diego.

Pittsburgh dropped the opener to the Padres 2-0, then suffered a 5-2 loss Tuesday night. All-Star pitcher Jeff Locke was roughed up in the setback and allowed four runs and seven hits in five innings. Locke didn't get much run support, as Marlon Byrd drove in both runs on a double in the third inning.

"Everybody's aware of where we are, what's going on," Pittsburgh manager Clint Hurdle said. "At the end of the day, we had a couple of opportunities we didn't capitalize on."

The Pirates are now one game behind the Cardinals for the NL Central lead, but lead the wild card race. The Cincinnati Reds, who sit 2 1/2 games behind in the division, currently occupy the final wild card spot.

Pittsburgh is 3-3 on its 11-game homestand and will give the ball to Charlie Morton on Wednesday. In 17 starts this season, Morton is 7-4 with a 3.54 earned run average and is 0-1 in his last two starts since winning four straight decisions. Morton did not record a decision in Friday's 5-4 loss to the Chicago Cubs and allowed three runs in five innings.

Morton is 2-2 in eight starts at PNC Park and has won both of his career starts against the Padres.

San Diego will try to spoil Pittsburgh's division title hopes once again and won for the 10th in 14 tries Tuesday night. Jedd Gyorko went 3-for-5 with a three-run homer and Ronny Cedeno had three hits and a run scored against his former team.

Padres starter Eric Stults allowed two runs on seven hits over five innings to earn his first win since July 14.

"It's definitely good to get (a win)," Stults said. "It's one of those things that maybe it'll be a little confidence boost, I've thrown some games where I've had some tough luck and others where I've put in a position to win and it just didn't happen."

The Padres are 5-3 on their 10-game east coast junket and hope Tyson Ross can find some success when he takes the mound Wednesday. Ross is 0-3 in his past six outings and lasted just two-thirds of an inning in Thursday's 10-5 loss at Philadelphia. He was reached for six runs and five hits to fall to 3-8 in 32 games (13 starts) this season.

Ross lost to the Pirates back on Aug. 20, when he permitted five runs, four of which were earned, and six hits in 6 1/3 innings of an 8-1 loss at Petco Park.

San Diego lost that three-game series versus the Pirates from Aug. 19-21 and went 5-1 against Pittsburgh last season.