Jason Witten led the Cowboys in receptions the last five seasons, the most obvious indication of the importance of the tight end whose status for the season opener is in doubt.

But the absence of Witten against the Giants wouldn't just take away Tony Romo's security blanket. It would force Jason Garrett out of his comfort zone as a play caller.

It's not just about how Witten's work in the middle of the field opens up the passing game. It's about the use Garrett's favorite formations.

Garrett loves operating out of two- and three- tight end sets. According to Football Outsiders, the Cowboys used more than one tight end on 53 percent of their offensive snaps last season, the third-highest rate in the NFL.

The Cowboys were especially effective with one running back and two tight ends on the field, a personnel package that can be used in a variety of formations because of Witten's versatility. They averaged 7.0 yards per play with "12" personnel last season, their best of any package they used at least 5 percent of the time.

How often can they do that against the Giants if Witten is in street clothes and Martellus Bennett is on the opposite sideline?

John Phillips should be a solid backup, but his career catches total (22) is a decent month for Witten, and he's nowhere near as powerful a blocker as Bennett. James Hanna has great speed and has blocked better than anticipated so far this summer, but he's still a sixth-round rookie.

Garrett's solution could be to go with what was the second-most effective, yet much less utilized, personnel package last season. The Cowboys averaged 6.5 yards per play out of "21" personnel, putting two backs and one tight end on the field, a group they used only 13 percent of the time in 2011.

Using that package more often without Witten especially makes sense considering that the Cowboys believe they upgraded at fullback by signing Lawrence Vickers.