But lately, it's buckled, along with the Cardinals' NL Central lead.After another uncharacteristically poor pitching performance, St. Louis will look to staff ace Adam Wainwright to right the ship Saturday against the Oakland Athletics.The Cardinals starters' ERA of 3.14 this season leads baseball, but they've posted a 6.75 mark during a 1-5 stretch after a 6-1 loss at Oakland on Friday. The defeat dropped St. Louis (48-31) a game behind Pittsburgh -- which defeated Milwaukee 10-3 -- for first place.Shelby Miller tied the team's second-shortest start of the season, getting pulled after 1 2/3 innings -- seven days after Tyler Lyons also recorded just five outs in a loss to Texas. All five runs and five of the six hits charged to Miller, an eight-game winner who had lasted at least five innings in every start this year, came in a second inning during which he threw 51 pitches. That's the most in one inning by any pitcher this season.Wainwright (10-5, 2.31 ERA) ranks among baseball's top 10 in ERA, but he'll have to end his own two-game losing streak. He didn't agree with manager Mike Matheny's decision to pull him from his last start against Texas on Sunday.The right-hander had thrown six scoreless innings, then was yanked after surrendering two two-out hits in the seventh, the second of which brought home the Rangers' first run. That was enough for Matheny, who commented later that Wainwright had been "laboring.""He's wrong," Wainwright said. "You don't want to call your manager out and I would never do that. Laboring is not what I was doing."Wainwright threw 105 pitches as he averaged 15.8 per inning, compared to 14.1 on the season."No, I didn't want to come out of that game," he said. "I felt I was as strong or stronger at the end than I was in the beginning."After two straight losses at home, Wainwright could be helped by hitting the road, where the Cardinals have won all eight of his starts -- he's 7-0 in that span -- since an opening day loss in Arizona.Wainwright will have to deal with a couple of hot bats for the Athletics (47-34). Jed Lowrie went 1 for 3 with a double Friday and is batting .464 during a seven-game hitting streak. Josh Donaldson, who had homered in each of his previous two contests, went 2 for 3 and is at .359 with 10 RBIs in his last 11 games.They'll look to back Jarrod Parker (6-6, 4.27), who hasn't lost in six starts since May 22. He's 4-0 with a 2.34 ERA in that span, surrendering 25 hits over 42 1/3 innings.The right-hander yielded three runs -- all on two homers -- over seven innings in a 6-3 loss at Seattle on Sunday.Parker, who faces the Cardinals for the first time, is 2-0 with a 1.35 ERA in his last three interleague starts.Wainwright has never pitched against Oakland.Matt Carpenter went 2 for 4 on Friday and is batting .382 during an eight-game hitting streak.