"He gets better every single day and it really goes to the kind of young man he is, how important it is to him," coach Jason Garrett said. "He just works at it and he has great juice, got a bounce in his step all the time, has a smile on his face. He loves to play football."
Dunbar has made an impression on Tony Romo, as well.
"I think the nice surprise really was Dunbar coming onto the scene last year a little bit," Romo said. "He’s had a great offseason. I’m excited about just having the ability to move (the ball with him). DeMarco (Murray) is such a special player that the ability to have a guy who can come in and hopefully do some things that still help us and have some juice, Dunbar has that. Then, we have some other guys who are competing, as well, afterward that’ll be good to see, (Joseph) Randle and (Phillip) Tanner."
In nearly two weeks of training camp practices, Dunbar has displayed speed and quickness and kept Tanner and Randle at bay and is currently the No. 2 back behind Murray.
"It's more of a feel thing," said Dunbar, who attended North Texas. "Last year I was out there and didn’t know where I was going, just running around out there. Now I have a feel for the offense and the way the O-line blocks it and I understand the scheme, so it’s a little easier."
Dunbar spent last year waiting for his chance behind Felix Jones and Murray. The Cowboys kept him around in the offseason and have given him a chance to become a third-down back who Romo can trust to dump passes off to out of the backfield. Dunbar has done that portion of his game well, and he's showing the coaches and scouts he can hit holes quickly and take hits.
Dunbar's diminutive size (5-foot-8, 188 pounds) puts him at a disadvantage in the pass-blocking game because he's got bigger defenders charging at him. But Dunbar sometimes will use a chip block and release quickly from the line of scrimmage and dash up field to make a play.
So it's easy to understand why the Cowboys use the word juice to describe him.
But what does it really mean?
"Speed. Explosiveness. Another gear, I guess you could say," Romo said. "A little start and stop. Quick stop. All those things. He has that, and that’s a good thing."