The Dallas Cowboys broke though last season. They won the NFC East for the first time since 2009, and won their second playoff game in the 21st century.

Obviously one of the biggest reasons the Cowboys had so much success last year was because of DeMarco Murray. Murray had a phenomenal 2014 season, leading the league with 1,845 rushing yards and 13 rushing touchdowns. His 1,845 rushing yards record is the biggest in franchise history, breaking Emmitt Smith's previous mark. But, as we all know, Murray was not re-signed and is now a member of the Philadelphia Eagles.

One could hardly blame the Cowboys for letting Murray walk. Dez Bryant was first priority.

The big question now in Dallas is: Can the Cowboys running game still perform at a high level?

Tony Romo and Bryant will still be the primary players on this offense. This year the Cowboys may pass the ball more than last season because of Murray's departure. Cole Beasley, Terrance Williams and Jason Witten help create a dynamic passing attack. Joseph Randle and Darren McFadden have a huge responsibility replacing Murray this season.

Two heads can be better than one, but the situation also has its disadvantages.

With Murray and McFadden running a two back system, the Cowboys won't be able to have as many tight ends or wide receivers on the field at the same time. Having an elite running back is beneficial because it allows you to input more players on the field and keep the same system. On the other side, there are advantages to having two featured backs. With McFadden and Joseph sharing carries, the Cowboys have more of a backup plan in case of an injury or lack of performance.

Randle had a solid year last season averaging 6.7 yards per carry. It's extremely unlikely Randle will average more than six yards per carry again, but the 23-year-old shows promise. The biggest reason Randle could thrive this year as the starter is because of the Cowboys offensive line. The Cowboys front five is highly regarded as the best in the NFL today, and many believe that was the prime reason Murray was so successful.

McFadden is young and talented, but health is always the biggest concern with him. Already McFadden has a hamstring injury, and some doubt is starting to creep in. Only once has McFadden run for more than 750 rushing yards in a season, which happened in 2010.

NFL free agent Steven Jackson has shown his desire to play with the Cowboys multiple times this offseason. It doesn't appear as if Jerry Jones will sign the veteran back.

McFadden and Randle should be able to complement each other well. The odds of the Cowboys rushing attack being even better than last season are slim, but with this offensive line, anything is possible.

Follow Damon Salvadore on Twitter @DamonSalvadore1