Once upon a time Sunday's game between the Patriots (3-0) and Cowboys (2-2) at AT&T Stadium was circled on the NFL schedule as a big game in Big D:

But Dallas has been decimated by injuries that not only hurt the team, but have sucked the star power from what could have been a tremendous inter-conference shoot out.

Playmaking quarterback Tony Romo and all-world wide receiver Dez Bryant are out of action, leaving future Hall of Fame tight end Jason Witten as the biggest star with a star on helmet for the home team in this matchup. The bulk of the star power will now be provided by a heavily-favored Patriots team that brings Tom Brady, Rob Gronkowski and a potent attack to put up points on the oversized scoreboard that hangs above the field at arguably the nicest stadium in America.

Even the media and fans of America's Team are expecting New England to roll into town and roll right over the home squad in a game that's lost much of its luster.

From a Patriots perspective, according to Brady, there is plenty to accomplish as his team returns to action after the bye.

"There is no letdown for us," Brady declared. "We're trying to establish a certain level of play. We've got off to a decent start this year, so we have to keep it going. We have to sustain good practices, good games, good weeks and see if we can just keep building.

"This team could easily be 4-0. They are playing at home. They have a lot of good players. They are a very talented team. … It's going to be a big test for our team."

The fact that Brady feels that way and that Belichick is able to convince his team to take such a mindset is why the Patriots are unlikely to have a letdown on Sunday, even if the matchup is admittedly a bit of a letdown from the marquee battle that fans were initially expecting.

The undermanned Cowboys are fighting to stay above water until their stars return to action. The Patriots are battling to establish a high level of play and set the foundation for another Super Bowl run.

It's America's Team vs. the top team in the NFL for more than a decade now. It's a rare battle between two of the most valuable sports franchises on the planet and one, despite the injury situation, that's worth savoring.

Here are a few things to keep an eye on as Brady leads New England's against Jerry Jones' banged up 'Boys:

In the trenches - It's a generally accepted belief - one backed up this week by Belichick's own comments - that the Cowboys have the best offensive line in the game. Depending on health circumstances, it's also not a stretch to say that the front seven might be the strength of the D in Big D. Given the injuries at quarterback and receiver, it would make sense that the Cowboys would try to control the line of scrimmage, and the clock, on offense by trying to run behind their talented offensive line. That's even more likely against a Patriots front that's allowed 4.7 yards per carry this season, although the addition of Akiem Hicks might help in that area. But playing without DeMarco Murray, Dallas hasn't run the ball all that well through four games. Joseph Randle is averaging just 3.9 per carry, while Darren McFadden is at just 3.5 yards per attempt. So both the Patriots run defense and the Cowboys run attack will have something to prove. On the flipside, New England's new-look, rotation-filled, young offensive line will deal with the schemes and rotational bodies that the Cowboys front will throw at it. If the Cowboys have eyes on an upset, it may have to start in the trenches.

A nice Tex-Mex spread - Sure Dallas would love to get after Brady. Most defensive fronts want to. But they can't, because the New England passing attack is spreading things out and getting rid of the ball as quickly as any unit in the game, maybe as quickly as any unit has done in a long time. The Patriots have used a pass-first spread approach through the first month and that should continue in Dallas. That means more Dion Lewis. More quick throws to Julian Edelman. More Rob Gronkowksi trying to take advantage of a suspect middle of the Cowboys pass defense. Brady has had a lot of success over the years against Rod Marinelli defenses and there is no reason to expect that to change in this one. The Cowboys are allowing a combined 92.7 passer rating this season and nearly three passing touchdowns per game. Their pass defense is ranked right behind the Patriots much-doubted unit. Brady's early season success should continue in Dallas, even if it does take him a bit to get used to a rare unfamiliar environment in AT&T Stadium.

Nothing big in D - Upsets are almost always driven, in some way, by big plays. The Patriots need to ensure that doesn't happen in Dallas. That means the offense needs to continue to play clean football. Brady doesn't want to make the errant throws that lead to interceptions. The other skill players need to hold onto it when they have it, including Dion Lewis as the back looks to play another clean game after his early-season fumbles. On defense the plan must be to keep the Cowboys from big plays. Tackle well and keep everything in front to live to play another down. New England has allowed a few too many guys to get behind the secondary this season. Surely Dallas would like to see that happen with Terrance Williams. The Patriots pass defense is very much a work in progress with both Bradley Fletcher (hamstring) and Tarell Brown (foot) both on the injury report and having missed the Jags game. Hard to imagine the Cowboys pulling off this unlikely upset without big plays on offense (long touchdowns) and defense (turnovers).

Hardy's 'Boys - Greg Hardy is a controversial figure. Last we saw him in 2013, he was also an elite edge player with 15 sacks for the Panthers. Now he returns from more than a full season away from the field. He talked earlier this week about being ultra-focused on sacking Brady. He also said a lot of other things that paint him in a very unflattering light and probably got under the collective skin of Brady and the Patriots. Unstable might be a word to describe how Hardy came off in his comments. That's not exactly the kind of guy you want targeting your franchise quarterback. Right now it looks like the only thing that could derail the Patriots is an injury to a key player. Hardy will come across both Gronkowksi and Brady on many of whatever snaps he plays on Sunday in his return to action in Dallas. Maybe he's rusty. Maybe he's not in shape. But maybe he also unleashes more than a year's worth of frustration on Brady and the Patriots. New England needs to deal with Hardy and Patriots Nation needs to hope he doesn't get anywhere near No. 12. It's also worth watching to see if Brady or his teammates do/say anything in response to Hardy's unprofessional comments about the quarterback's wife and sister-in-law.

Third down - It's the money down in football that often separates the men from the boys. This week it could be the down that separates the Patriots from the 'Boys. Dallas just isn't very good on third down. The Cowboys can't stay on the field, ranking 25th in the converting just 34.1-percent of its third down chances offensively. Defensively, the Cowboys rank 27th in the league, allowing teams to convert on 44.1 percent of their chances. And New England is converting at a 60-percent clip so far this year. If the numbers hold true, although the Patriots third down defense ranks 24th in the NFL, it very much favors the visitors. New England stays on the field on offense. Dallas does not. And can't get off the field on defense. That's a bad combination for a team looking to find a way to win an upset. 

Prediction- While this looked like a star-filled battle when the NFL schedule came out last spring, the reality of NFL injuries has killed that storyline. Instead, it's a chance for the Patriots to extend a four-game winning streak against the Cowboys and improve on their AFC-best 42-10 record against NFC foes dating back to NFL realignment in 2002. The fact is you have to really work hard to come up with a way that Brandon Weeden and the Cowboys could win this game. And any scenario of that happening would include plenty of good luck for the home team and mistakes from the visitor. That combination just doesn't seem likely. More likely is that Brady and his weapons do what they've been doing for the first three games. That means spread sets, quick throws and impressive drives to points. The two most unstoppable forces in the NFL this year are Gronkowski and Atlanta's Julio Jones. Jones had 160-plus yards and two scores a couple weeks back in Dallas. Now Gronkowski gets his turn as he looks to get to 60 touchdowns faster than any tight end in history. Defensively the Patriots should have a lead to play with to help deal with the Cowboys running game and overall attack. I just can't see Weeden putting together long scoring drives on his checkdown throws and focus on one side of the field. Upsets happen and are often hard to predict. So I won't. The Patriots cruise to the 42-10 win in a game that's nothing like what we had expected prior to the season. And they might even put up more points than that thanks in part to Jerry Jones' Deflategate comments this offseason and Hardy's talk earlier this week.

What other things will you be watching for in this Patriots trip to Texas? Let us know with a comment below!