Updated

Monte Kiffin fields questions about the greatness of his Dallas defense one week, and how bad it is the next.

Brandon Carr goes from an elite cornerback befitting a $50 million contract to the guy who gave up 329 yards in one game to Detroit's Calvin Johnson.

It's hard to figure out what the Cowboys have on defense. They've won games with takeaways and flashes of dominance, but now carry the dubious distinction of being the only unit in NFL history to allow four 400-yard passers in one year.

That's with half the season left, and Drew Brees and Aaron Rodgers still to come.

"We've been on a roller coaster," said Kiffin, the 73-year-old defensive coordinator who replaced Rob Ryan and brought a scheme that was supposed to be a little more conservative. "Two pretty good games in a row and wanted to really get that third one. We'll come back. We have to do it."

The Cowboys were leading the Lions even though Matthew Stafford already had become the fourth quarterback on that 400-yard list against Dallas, which had never allowed more than one in a season, according to STATS. But Stafford led an 80-yard drive in less than a minute with no timeouts, scoring on a 1-yard lunge with 12 seconds left for a 31-30 win.

Stafford finished with 488 yards passing, the most Dallas has ever allowed. That was one week after the Cowboys became the first road team since San Diego in 1984 to hold an opponent averaging at least 27 points a game to a field goal or less in a 17-3 victory against Philadelphia.

"You see these guys, these elite quarterbacks that are pretty much like coaches that can run the show and put guys in position to make plays, anything you do can be wrong because they always have an answer for it," Carr said. "It's a learning experience."

The Cowboys figure to get a one-week break in the passing game because Minnesota is bringing a messy quarterback situation to Texas, with coach Leslie Frazier saying Wednesday he was still undecided between previously benched Christian Ponder and Tampa Bay castoff Josh Freeman.

Of course, Adrian Peterson is coming to town. Dallas kept NFL rushing leader LeSean McCoy under control in the win over the Eagles, but couldn't do the same against Reggie Bush even when the defense was aligned to stop the run. The Cowboys gave up a franchise-record 623 yards in total offense to the Lions.

"It's one thing to have the big receiver making a lot of plays outside but they consistently ran the ball on us, which was disappointing," coach Jason Garrett said. "You have to take the real good players out of the game as best you can, and it's hard to do it."

On Detroit's final drive, Dallas had rookie Jakar Hamilton at safety a day after he was called up from the practice squad. He was out there because Barry Church had tweaked a hamstring.

While Church is expected to return, cornerback Morris Claiborne is likely to miss a couple of weeks with a hamstring problem. That could press another rookie, B.W. Webb, into extensive action unless Dallas adds a defensive back.

An injury-riddled defensive line could get end DeMarcus Ware (quad muscle) back this week, but the heavy rotation will continue with players who were either expected to be backups or weren't on the roster at all when training camp started.

"Well, we certainly have a lot of new guys playing," Garrett said. "We know that, we recognize that. But there are no excuses. If a guy has got a helmet and shoulder pads and a chin strap, we have an expectation that he's going to do things the right way."

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