Football has always been a game of blocking and tackling.

But the updated NFL version features the three Ps: pass, protect and pressure.

The quest of every NFL team is to find a franchise quarterback. When you find one, you must protect him because he'll be wearing a bull's eye. Defenses know they must pressure him. Pound him. Sack him. The more you hit a quarterback, the less of a factor he becomes.

The league has crafted that formula.

Check out the last seven drafts - in particular, the top five picks of every draft since 2007. Of those 35 premium selections, there have been eight quarterbacks, nine offensive tackles and nine defensive linemen.

Quarterbacks have their own draft board. But you need to go high for those difference-making wide bodies.

That could cause problems for the Cowboys next month.

Their first, second and probably third priorities in this draft are the defensive line. With the departures of DeMarcus Ware and Jason Hatcher this off-season, the Cowboys lack the quality and quantity up front for the scheme new coordinator Rod Marinelli hopes to craft.

Marinelli wants a deep rotation that can attack the quarterback in waves. But right now, his Hatcher- and-Ware-less front can barely create a ripple, much less waves.

Now the problem: The Cowboys have the 16th pick in the first round. But in four of the last six drafts, only the sixth-best defensive lineman was available at the 16th pick.

The Cowboys could use another Russell Maryland on the inside and Ware outside. But Maryland was the first pick of his draft and Ware the 11th pick of his. The Cowboys are drafting too low to find that type of impact defender in this draft.

The Cowboys have done their homework. They know Jadeveon Clowney, the best end in the draft, will be long gone by the time they go on the clock. Edge pass rushers Anthony Barr and Khalil Mack, a couple of athletic, speedy linebackers who are possible defensive end conversions, also figure to be gone.