The Cowboys' projected starting defensive line is Anthony Spencer, Jason Hatcher, Jay Ratliff and DeMarcus Ware.

Three of the four starters -- Hatcher, Ratliff and Ware -- are in their 30s, and Spencer and Hatcher are entering the final year of their contracts. At some point, the Cowboys will have to get younger or give Hatcher and/or Spencer a new contract.

One projected future starter is defensive end/tackle Tyrone Crawford, a third-round pick in 2012.

Crawford has a chance to become a starter -- maybe not this year, but in the future -- given the contract and age status of the defensive line.

"For me and every single guy on the defensive line, they will tell me and even the vets like Hatch and Rat, go into every year trying to be a starter," Crawford said. "That's what I do every year, even if I don't get the starting spot. I'm playing like a starter when I'm on second string. We all have big roles. If we can fill those roles this year like we're starters (playing) on the second string, we might have one of the best defensive line in the NFL."

Crawford was drafted as a defensive end, but in this new 4-3 scheme, defensive coordinator Monte Kiffin is asking him to play end and tackle. Crawford said everybody on the defensive line has to know all the spots.

"With this defense, there's not really a challenge not knowing your assignment," Crawford said. "You pretty much have to know everybody's assignment."

And Crawford likes what defensive line coach Rod Marinelli is doing with the defensive line. He's taken the sign down outside the defensive line room and changed it from defensive linemen to "rushmen."

"I like what were doing with it," Crawford said. "We don't have a D-line room anymore. We're all rushmen. We're all fast guys."