FRISCO — The Cowboys' run defense is a major issue right now. The numbers would indicate it is a middle of the pack unit.

It is ranked 19th in rushing yards allowed (507), ninth in most rushing first downs allowed (35) and 20th in rushing yards allowed per game at 101.4.

And the one stat that sticks out is the Cowboys are 5-13 the last three seasons when allowing a rusher to gain 100 yards or more.

Dallas faces the New York Jets at MetLife Stadium on Sunday. The winless Jets employ Le'Veon Bell, a shifty runner considered one of the best in the league. Bell has struggled behind an inept offensive line where the best he's been able to do is 68 yards in Week 2 against the Browns.

Bell runs off the edge, dips and dodges past defenders, and waits patiently before making a move. This causes headaches.

"It's the ultimate test this week because [Bell's] a guy that can be anywhere at any time," linebacker Jaylon Smith said. "You got to do your job."

That's been a problem.

The Cowboys have failed at gap control. The defensive linemen have to maintain their gaps to allow the linebackers to stay sound and play their lanes. The defensive ends must set the edge forcing running backs or mobile quarterbacks to head back inside.

When someone messes up, the whole operation falls apart.

"I also notice where teams want to attack us," defensive end DeMarcus Lawrence said. "It's on the outside. It's the perimeter, checkdown. We see all that, we take that into consideration and you got to get better from it."

In addition to facing Bell, a swirling target, the return of Jets quarterback Sam Darnold presents a problem because of his ability to move in the pocket.

"Aaron Rodgers moves pretty well," Lawrence said. "Teddy Bridgewater moves pretty well. Everybody moves pretty well. Baker Mayfield moves pretty well. We don't even play him. Who cares? It's the standard."

Lawrence indicated his group needs to play with more of an edge. He called it "swag" because when that happens you see more impact plays on the field.

In last week's loss to the Packers, the Cowboys missed 12 tackles, an alarming number considering the team has a Pro Bowl defensive end (Lawrence), Pro Bowl linebacker Leighton Vander Esch and a rising talent in Smith.

"It's something that can't happen," Smith said. "It's the National Football League, and it's all about how you respond. So we're dialing in on our angles, tackling techniques, just overall collectively, defensive efforts."

The lack of discipline must be solved against the Jets and even if that's accomplished, few will give the Cowboys credit.

The Jets have rushed for 264 yards, second-fewest in the NFL. To put it in prospective, Ezekiel Elliott has rushed for 386 yards through five weeks, which is considered a low number for him.

Where the Cowboys will be judged is the game against the Eagles in two weeks. Philadelphia has the sixth-most rushing yards in the league at 559 and has produced at least 100 yards rushing in three of their five games.

That's two weeks from now, and the NFL remains a one game at a time business.

"We have to execute and do our job," defensive end Tyrone Crawford said. "The reason why big runs happen is because somebody is not in their gap."

Lawrence and Crawford spoke with an edge in their voices Wednesday because they know about the standards coming up short. In meetings, defensive coordinator Rod Marinelli and passing game coordinator/defensive backs coach Kris Richard reminded everyone of that.

"But that's exactly what we expect," Crawford said. "We don't expect our coaches to react good after a game like that because we're obviously harder on ourselves than anybody can be. They have to be trying to match that intensity to make sure we're on it and we're going to get better on the things that we mess up on."

Smith said the coaches have "been direct as they always are."

Vander Esch and Smith have struggled at tackling on a consistent basis and taking better angles on ball carriers. The defense has to play more physical and complete more open field tackles.

This is a perfect week to fix the problems and make sure they don't return.

"It's not rocket science," Smith said. "Just basic fundamentals. You have to hound in on it each and every week if you want to succeed."