ARLINGTON, Texas – Lance Dunbar knew he had to light it up Wednesday night to have any kind of chance of sticking on the Cowboys’ roster.

The undrafted rookie running back will find out soon whether a dominant performance against the Dolphins was good enough.

Dunbar dashed through the Dolphins’ defense for 105 yards and a touchdown on 15 carries. It was the first real opportunity for Dunbar, who had only one previous preseason carry, to flash the talent that made him the all-time leading rusher in North Texas history.

“I know it feels good,” said Dunbar, who missed most of training camp and the first two preseason games with a strained hamstring. “I was kind of stressing myself out. I knew it was a big day. It was all or nothing for me today. I did what I can do.”

The highlight of Dunbar’s night – and the game, for that matter -- was a spectacular 58-yard touchdown run. Dunbar, who called the moment “a dream come true,” made a few Miami players miss with a spin move in the hole and outran everyone else en route to the end zone.

“I was so tired, I couldn’t even remember,” the 5-foot-8, 191-pound Dunbar said when asked to describe the run. “I had to see the replay first. I made a backside cut. The defense overflowed and I made two or three guys miss with a stiff-arm and squeezed my small self through there and finished the run off.”

Head coach Jason Garrett made a point to praise Dunbar.

"I thought Dunbar ran the ball really well," Garrett said. "He showed his lateral quickness his ability to burst through a hole and obviously make big runs. He's a tough guy, not afraid to stick it up in there."

It’s still likely that Dunbar, who also gained 35 yards on three punt returns, will get caught up in the numbers crunch at tailback.

Phillip Tanner has a firm grasp on the third running back role he filled last season. Tanner, a proven special teams performer and solid pass protector, rushed for 48 yards and a touchdown on nine carries against the Dolphins.

Dunbar and Jamize Olawale, a fellow undrafted rookie out of North Texas who rushed for 53 yards on seven carries against the Dolphins, have positioned themselves to at least be strong candidates for the practice squad.

It is possible, however, that the Cowboys could opt to keep four running backs, as they did at the beginning of last season.

Dunbar definitely gave the team’s decision-makers something to think about as they make their cuts.