CINCINNATI – Players slumped in their padded folding chairs, staring blankly at the floor, their lockers or each other. The only sound was the harsh scrape of brushes cleaning metal spikes as the attendants did their job.

The Cardinals’ clubhouse had the look and the sound of a season slipping away.

Adam Dunn hit a grand slam and a solo homer off Mark Mulder, and the Cincinnati Reds extended the Cardinals’ late-season slump with a 7-2 victory Tuesday night.

The defending World Series champions have dropped five in a row, matching their season high. After regrouping for an impressive comeback, the Cardinals have started unraveling down the stretch.

They were 10 1/2 games out at the end of June, but had rallied to within a game of first place in the NL Central before they hit their current skid. The loss left them four games out, their biggest deficit since Aug. 24.

“It’s just tough,” said right fielder Rick Ankiel, who played a big part in the loss. “These are big games to lose, and we are not playing to our potential, which makes it that much worse.”

Ankiel lost a fly ball that dropped for a double, then let another deflect off the heel of his glove for a two-run error during Cincinnati’s six-run third inning. Dunn, who hit a solo homer in his first at-bat, hit his seventh career slam off Mulder (0-2) during the 10-batter inning.

Essentially, that was it.

“In this ballpark to give up extra outs?” manager Tony La Russa said. “We gave up two of them. That’s more the story than Mark’s pitching. A strange inning. We mugged the two balls.”

David Eckstein and Ryan Ludwick hit solo homers off Matt Belisle (8-8), who allowed six hits in seven innings.

There was more bad news for St. Louis before the game. Outfielder Chris Duncan is out for at least 10 days – and possibly for the season – because of a sports hernia that will need surgery at some point. Also, third baseman Scott Rolen had season-ending shoulder surgery.

The Cardinals’ rotation was the foundation for their about-face. It’s been a big part of their recent downturn.

The 30-year-old Mulder hoped to shore it up by making his comeback from left shoulder surgery last Sept. 12. He rejoined the club and gave up six runs in four innings of an 8-2 loss to Pittsburgh last Wednesday.

He lasted four innings again in his second start. The Reds piled up seven hits and seven runs, aided by Ankiel’s misadventures.

“There are still some things that are tough for me to throw when I want to and when I need to,” Mulder said. “I didn’t make good pitches in that inning. In that inning, the ball was up and hittable.”

Ankiel was one of baseball’s feel-good stories last month, when the failed pitcher made his return to the majors as a slugging outfielder. He hit a grand slam and drove in nine runs during a three-game sweep of the Reds from Aug. 31 to Sept. 2.

Since then, he’s come under scrutiny for reports that he received shipments of human growth hormone in 2004, before it was banned by Major League Baseball. A few fans chanted “HGH!” when he came to bat and grounded out in the eighth, leaving him in an 0-for-17 slump.

Ankiel’s defense was the main problem on Tuesday.

He got under Ken Griffey Jr.’s fly to the warning track, then lost it in the sky.