Tony Romo Dez Bryant
Tony Romo and Dez Bryant give the Dallas Cowboys one of the best offenses in the NFL. Getty

Last season ended on a sour note for the Dallas Cowboys, as a controversial call prevented them from advancing to the NFC Championship Game. But Jason Garrett's squad is coming off their best season in nearly a decade, and they should be able to continue that success in the 2015 NFL season.

Dallas went 12-4 last year, winning the NFC East, as well as a playoff game. The Cowboys had a chance to defeat the Green Bay Packers in the divisional playoff round, and what looked to be an incredible catch by Dez Bryant in the game’s final minutes was ruled an incomplete pass, ending Dallas’ pursuit of a title.

Few teams made more news in free agency than the Cowboys. Jerry Jones lost one of the biggest players on the market, made the most contentious signing of the offseason and secured the top playmaker with a long-term deal.

Here’s a breakdown of the Cowboys' depth at every position, along with grades for each spot and an overall conclusion to how 2015 could play out.

Quarterback

Tony Romo is coming off the best year of his career, and there are plenty of reasons to believe he’ll have another terrific season. The four-time Pro Bowler is often under more pressure than most NFL players, but he won’t face as much criticism heading into this season because of how much success the Cowboys had in 2014. The skills and mechanics are still there, and most importantly, the motivation. Behind Romo is Brandon Weeden, who has enough experience and skill to fill in, if needed.

Grade: A-

Receiving Corps

Dallas made Dez Bryant the NFL’s second highest paid receiver for the upcoming season, and the lifelong Cowboy has certainly earned it. Given the numbers he’s put up over the last three seasons, Bryant is a lock to at least total 1,200 yards and 12 touchdowns. No.2 wide receiver Terrance Williams disappeared at times last year, and he doesn’t give Dallas the one-two punch compared to some of the league’s top passing offenses. But he’s looked good in OTAs, and he has a chance to put up the best numbers of his career. Cole Beasley only totaled 420 yards in 2014, but he was much more productive in the second half of the season and could have an even greater impact in 2015.

Jason Witten is no longer an elite tight end after putting up his lowest receiving total since his rookie season. But he remains a consistent option for Romo, even in his 13th NFL season.

Grade: B+

Running Back

With the departure of DeMarco Murray, the Cowboys suffered a major downgrade at the position this offseason. Murray was the key to the team’s offense, carrying the ball 392 times for 1,845 yards. Dallas did not replace him with a proven No.1 running back, and they are hoping that one of their three rushers emerges as the clear-cut starter. Joseph Randle might have the best chance to become the Cowboys’ top rusher, though he’s had his share of issues off the field. Darren McFadden was a below-average performer with the Oakland Raiders over the last three years, and Lance Dunbar has rushed for just 324 yards in his three-year career. If healthy, Ryan Williams may be a decent contributor if he effectively overcomes his injury woes and if Garrett decides to use four running backs.

The running game will be a key to Dallas’ success in 2015, and despite the lack of star power at running back, the team can still total a lot of yardage on the ground. Randle has produced when given the chance, averaging 6.7 yards per carry on 51 attempts last year. Murray took advantage of an elite offensive line last season, and Randle should be able to do the same.

Grade: C+

Offensive Line

Garrett can sleep well at night knowing he has plenty of protection for Romo. The unit might have been the best in football in 2014, and it could be even better in 2015. Dallas has some of the NFL’s best young linemen, and they might have added another one in the draft. Left tackle Tyron Smith was selected as a starter in the 2014 Pro Bowl, and first-round draft picks Zack Martin and Travis Frederick will continue to improve in their second and third years, respectively. La’el Collins was talented enough to be taken in the first round of this year’s draft, but he went undrafted because his name was linked to a murder investigation. Signing as a free agent with Dallas, Collins could end up being the team’s starting left guard, but he will be tested by Ronald Leary.

The offensive line will give Dallas’ running backs plenty of holes to run through, and most importantly, keep Romo upright and healthy.

Grade: A+

Front Seven

There is a lot of potential from Rod Marinelli's group. The front seven could have been better a year ago, and new faces have arrived. Defensive end Greg Hardy should be the team’s best pass rusher, but a domestic violence arrest kept him off the field for all but one game in 2014, and he’ll miss the first four games of 2015 with a suspension. It wouldn't be surprising if the 26-year-old plays with extra motivation. Second-round draft pick Randy Gregory fell in the draft because of failed drug tests and behavioral issues, but he is considered a serious talent with a high ceiling. Tyrone Crawford is one of the best kept secrets in the NFL, and could be poised for a monster season. Another Boise State star, DeMarcus Lawrence, has great speed and size, and should be improved as he switches to the left side.

Linebacker Sean Lee will return this season, having missed all of last year with a torn ACL. Lee might have been the team’s best defensive player last year if he was healthy. Rolando McClain is recovering from knee surgery and will be suspended for four games for violating the league’s substance abuse policy. But he played well last year, and Lee and him will help give the Cowboys a solid linebacking corps. Anthony Hitchens and Kyle Wilber will battle for playing time, and both should do a steady job. Meanwhile, new addition Keith Rivers has plenty of experience and could be the answer at outside linebacker.

Grade: B

Secondary

The Cowboys have endured problems against the pass in recent seasons, and the secondary isn’t expected to see huge improvements from 2014. Dallas drafted a cornerback with their first pick because it was their biggest area of need. There are high hopes for Byron Jones, who is an exceptional athlete, but the rookie is no guarantee to make a significant impact next season as he makes a big adjustment from the American Athletic Conference. Brandon Carr had his struggles during stretches, but looked considerably better over the final six weeks. Orlando Scandrick earned a new contract with his play last season, and he is the most steady player of the entire group. The x-factor is Morris Claiborne, who may have finally put his injury problems behind him.

Dallas’ secondary was not helped by the fact that the front seven had trouble getting to the quarterback in 2014, and an improved pass rush should make their job easier.

Grade: C+

Special Teams

The Cowboys have an average special teams unit, but they are strong in one area. Dan Bailey is one of the best kickers in the NFL, and he usually gives Dallas an advantage over the opposition. He's very accurate from 50 yards or more, converting on five of his seven attempts last year. Chris Jones isn’t the best punter in the NFL, but he’s certainly adequate and does a good job of avoiding touchbacks.

Dallas’ biggest problem could come in the return game. Dwayne Harris is gone, and Dunbar might be his replacement on kickoffs.

Grade: B-

Coaching

It's funny how winning can change people's perceptions about a coach. That's been the case with Garrett, who enters the 2015 season with job security. Garrett has improved on his in-game coaching, and he communicates well with Romo. This offense belongs to Romo, who after so many seasons running the offense is basically a coach at this point. On defense, Marinelli often keeps things simple, and that's smart considering the new faces on the roster. How he facilitates the growth of Jones and Claiborne might be crucial to the Cowboys' chances to go deep in the playoffs. Players rave about Marinelli, and his ability to get the most out of a pass rush.

Grade: B

Overall

The outlook for the Cowboys is bright. Even after losing the league’s top running back from a year ago, Dallas should be a top offensive team. With a stellar offensive line, an elite receiver and a steady quarterback, the Cowboys should put up a lot of points. The team has some question marks on defense, but they’ll be fine if a few things go their way. It might be difficult for Dallas to ultimately get by the Green Bay Packers or Seattle Seahawks to reach the Super Bowl, but they are the clear-cut best team in the NFC East.