Frisco -- Cowboys head coach Jason Garrett likes to say, "the runner matters"when talking about the impact running backs can have on the Cowboys offense. We're about to find out how much, in more ways than you may think.

Alfred Morris will lead a trio of backup runners trying to replace Zeke Elliott. A tall task considering Elliott has racked up 900 total yards, nearly 35 percent of the Cowboys offensive production this season.

Will we miss him? Yeah," says Morris, "but at the same time the train goes on, so we're going to do our job."

"We have great confidence in the guys that are going to play in his place," said Garrett.

Confidence, yes, but nowhere near the level it has been for Elliott.

Oct 29, 2017; Landover, MD, USA; Dallas Cowboys running back Ezekiel Elliott (21) carries the ball as Washington  and Redskins  chase in the fourth quarter at FedEx Field. The Cowboys won 33-19. Mandatory Credit: Geoff Burke-USA TODAY Sports

Here's an example. The Cowboys have gone for it on fourth down 12 times this season, more than all but one team in the league. Don't expect Garrett to be as aggressive now, it's the Zeke effect. The mentality changes because the runner matters.

That's just one of the ways no Zeke will translate into more work for the Cowboys defense.

As the Cowboys time of possession goes down, which it will without Elliott leading a clock-chewing offense, that defense will have to rise up. Those flashes of dominating play we've seen on the defensive side of the ball the last few weeks will have to become more commonplace.

The entire team will have to improve, but most of it falls on quarterback Dak Prescott. We know he's poised and resilient, but now the challenge of doing it without Elliott means striking the fine balance between doing more and avoiding trying to do too much

“It can get you in trouble thinking that for the most part. For me it’s about just staying focused on my job," Prescott said, "going out there giving this team a chance to win no matter if we’re handing it off or throwing it.”

Oh, and the zone read keeper close to the goal line that's worked so well for Prescott, and helped the Cowboys red zone efficiency spike in the month of October, yeah, that probably won't work now, either.

Because the runner matters.

And to what degree will decide of the Cowboys are still in the playoff chase when the runner gets back.