DeMarco Murray came alive in his rookie season in 2011. Murray put up 236 yards in his breakout performance (vs. St. Louis). 

It’s not four touchdowns in a single game, but Al Bundy would be proud of the display Murray put on last year.
Sadly, Murray went down with injury and Felix Jones handled the run-game responsibilities in typical mediocre fashion. 
Jones is coming off shoulder surgery. However, he showed up to camp out of shape, and is reportedly fatter than an explosive running back should be.

The Cowboys managed just five rushing touchdowns in 2011.
 Against the San Diego Chargers, a new running back stamped his place in history as the first Cowboy to score a touchdown in the 2012 season. Jamize Olawale, a former wide receiver out of the University of North Texas, deserves a spot on the Cowboys' roster at running back. 

Olawale is big.  And not in a ‘Felix The Fat’ kind of way. Standing, 6’1”, and 238 pounds, Olawale could be a beast at the position.
He possesses the physical traits necessary to be a difference maker around the goal line, and a suitable third-down running back. Olawale kept his legs moving and picked up additional yards whenever he got the opportunity against the Chargers.
In addition, Olawale demonstrated he can catch the ball. Something Jones is having an issue with lately. 
It is only preseason, but with Phillip Tanner chomping at the bit to get back on the field it seems plausible that Jones could be cut. And he should be cut. 
He blew this entire season when he showed up to camp out of shape. He continues blowing his shot with his lack of effort and performance. Murray put up only 30 yards in his second preseason game, but those rushing yards looked good enough to show Jones the door. 
One thing that makes the cut easy to swallow is that Jones isn’t out of shape and grossly over-paid like Albert Haynesworth. The Cowboys wisely waited on Jones to perform at a high-level and stay healthy prior to signing him to big deal. Smart move. 
Jones never lived up to the flashes of brilliance he showed early in his career, and it is time to let him go and look to the future.

Even if Murray gets hurt this season, Jones is not the answer at running back.