Dak Prescott and Ezekiel Elliott's names were on the tips of everybody's tongues last season when discussing why the Cowboys had their best record since 2007, but they wouldn't have won half of those games without the effort on Defense. Rod Marinelli has proven he can build above-average defenses with below-average talent, and he did it again last season as Dallas fielded a top-10 run defense and a "bend but don't break" pass defense. With many of their top defenders leaving in free agency, Marinelli has another challenge ahead of him in 2017.

CB

Brandon Carr and Morris Claiborne left in free agency, so Dallas used two of their top three draft picks on cornerbacks. Rookie CB's usually have a tough time adjusting, but the Cowboys picked up two very good prospects in Jourdan Lewis and Chidobe Awuzie in a stacked cornerback draft class. Orlando Scandrick will return as one of the league's better slot cornerbacks and Anthony Brown provided some solid play as a rookie last season.

S

The Cowboys lost their top two safeties in free agency with Barry Church and J.J. Wilcox gone, which will force them to move Byron Jones to safety full-time. Jones is one of the NFL's most versatile defensive backs, and he should have a big impact again next season.

The other safety spot is up for grabs with Robert Blanton, Jeff Heath, and rookie Xavier Woods all fighting for reps.

LB

Sean Lee has finally been able to stay healthy over the last two seasons, which has resulted in two Pro Bowls and an appearance on the All-Pro team. Anthony Hitchens is a very solid cover linebacker, and Cowboys fans will be excited to see Jaylon Smith hit the field in 2017 after sitting out his entire rookie season recovering from a serious knee injury.

DL

The defensive line in general isn't very strong in Dallas, but Marinelli has been successful in coming up with ways to get them into opposing backfields. The defensive end was the Cowboys' biggest need this offseason, and they spent a first round pick on Taco Charlton to attempt to fill that hole. That was about all they did to address that need, however, as they return three DE's from last year who often had trouble creating a pass rush.

DT David Irving started to look very disruptive in his second NFL season, and they'll want to see Maliek Collins improve after a so-so rookie year.

The Cowboys' defense suffered a ton of turnovers this season, and will be dependent on talented rookies to fill some important roles at defensive end and cornerback. Dak Prescott and Ezekiel Elliott will be outstanding again next season, but they'll need some key stops from this defense if they want to be Super Bowl contenders.