While Tony Romo and Philip Rivers will understandably dominate the headlines, it's the less heralded players who will decide whether their teams will boom or bust this season. Both teams have struggled to meet expectations in recent years, and with some unfortunate early injuries, they already face uphill battles in 2012.
That's why the following players must step up tonight and prove that they can be relied on.
Morris Claiborne, CB, Cowboys
It's an exciting night for Dallas fans, as Morris Claiborne, the Cowboys' prized rookie, will make his much-anticipated debut. Dallas selected Claiborne sixth overall in the 2012 NFL Draft, and the Cowboys are expecting him to develop into the shutdown corner they so desperately need.
How many quarters should Morris Claiborne play tonight?
Claiborne is bigger than most players at his position, and his speed, athleticism and ball skills are elite. He gave opposing receivers nightmares in the SEC, and although there will certainly be a learning curve, he should immediately improve the team's biggest weakness.
The Cowboys secondary has been their undoing for the past several years. Last season they gave up 244.1 passing yards per game, which ranked 23rd in the league.
Claiborne should give them a boost on the outside, as he is the most talented corner on the roster. He had some struggles in training camp, but after he underwent offseason wrist surgery, that was to be expected.
Claiborne is healthy now, and if he had his way, he would play the entire game tonight (h/t Star-Telegram.com).
I doubt the Cowboys will have him out there the entire time, but you will still get a great look at Claiborne this evening.
Ronnie Brown, RB, Chargers
The brittle Ryan Mathews will miss the next few weeks with a broken clavicle (h/t ESPN), and Ronnie Brown is the obvious replacement at this point.
Brown is a veteran back, and he's proven in the past that he can be a productive starter. Unfortunately, the 30-year-old is well past his prime, no longer possessing the explosiveness to break off big runs with consistency.
He struggled in Philadelphia last season, averaging just 3.2 yards per carry as LeSean McCoy's backup. He posted career lows in every meaningful category, often looking like a shell of his former self.
Of course, Brown has always had the talent to be a primary ball-carrier, and he may thrive in a more featured role. Tonight's game will be the perfect opportunity for him to show that he can still be a decent starter.
John Phillips, TE, Cowboys
Like Brown, John Phillips will be called upon to replace a high-profile offensive starter. Unlike Brown, Phillips hasn't had the experience of being the main option at his position.
Perennial Pro Bowler Jason Witten will be out for at least the next few weeks with an odd spleen injury (h/t cbssports.com), robbing Tony Romo of his favorite and most reliable target. Phillips obviously won't be expected to play as well as Witten, but he's got to become much more of a weapon than he's been in previous years.
In two regular seasons with the Cowboys, Phillips has just 22 receptions for 163 yards and a touchdown. Jason Witten used to put up similar numbers in single games.
So while it's unrealistic to expect a ton out of Phillips, the Cowboys offense will experience a major setback if he can't catch at least a few passes per game and draw some attention away from its receivers.
Be sure to keep an eye on him tonight.