Donnel Pumphrey doesn't take "no" for an answer. He has been told "since Pop Warner days" that he is too small to play running back. An FBS-record 6,405 rushing yards and 67 touchdowns later in four seasons at San Diego State, Pumphrey is in the NFL with the Eagles, looking to make his mark in the offense.

Just what that mark is going to be remains to be seen. The Eagles view Pumphrey as a weapon. How quickly he develops into a multipurpose playmaker – both from the line of scrimmage and in the return game – is the part of the equation that is unknown, which is why every rep Pumphrey takes is crucial.

"He's somebody who can do a lot of things with the ball in his hands," head coach Doug Pederson said. "Let's see how quickly he picks up the offense and in what ways we can use him. I could see him moving around the offensive formation quite a bit."

The idea of playing in space is exciting to Pumphrey, the diminutive running back who is listed in the team's media guide as 5-8 and 176 pounds. That's being generous. Pumphrey may or may not be an inch closer to 5-7, and he says he weighs in the range of 166 to 175 pounds. The Eagles would love if Pumphrey "bulks up" to the 180-, 185-pound range.

Whatever his height and weight, Pumphrey is a remarkably unique player, similar in height, but not in body structure, to his teammate in the next locker over, Darren Sproles. At 5-6 and 190 pounds, Sproles is a fireplug with a powerful lower body and dancing feet. He is sturdy. He has some power.

Pumphrey is slight and small but, boy, can he play the game of football.

"I was probably the smallest running back in college football history, maybe," Pumphrey said, discussing the "too small" label. "I've been told that my whole life. I continue to play with a chip on my shoulder and every time I take the field I play like I'm a big back. My dad and all my coaches saw it in me that I could make it to the next level. It's really all about believing in yourself. That's what has gotten me this far, so I'm going to continue doing that.

"I play with a big heart and that's really what I'm all about."

Smaller running backs aren't anything new to the NFL. Brian Westbrook was in the range of 5-8, 5-9 and 200 pounds and he is a member of the Eagles' Hall of Fame. Maurice Jones-Drew measured in at 5-8 and he had a wonderful career in Jacksonville. Barry Sanders, of course, is in the Pro Football Hall of Fame. Tyreek Hill, measured at 5-10 and 185 pounds, was a game-breaking player at the line of scrimmage and in the return game for Kansas City last season.

It can be done. It has been done. The key is that the Eagles learn as much as they can about Pumphrey and his skill set and put him in the best position to use his extreme quickness and burst to make it work. Pumphrey, for example, isn't likely to run 20 times a game out of the I-formation like he did at San Diego State. That just doesn't look like the right kind of fit for Pumphrey in the NFL.

In this weekend's Rookie Camp, Pumphrey showed some versatility. He ran pass routes out of the slot. He ran some routes from the backfield. The Eagles will give him some reps on jet sweeps and in the screen game and, yeah, he'll also get a long look in a more traditional backfield role.

  on the next snap and get the football in space in the running game.

"With players like that, you're excited to see what you can do with him," Pederson said. "That's what this camp is all about, to see how much we can use him and how much he can handle mentally and physically. We know what he can do with the football in his hands. We've just got to get him in the right position to be as effective as he can be."

We're in the very early stages here. Can Pumphrey be a home run hitter for the Eagles? Can he soak up every bit of intelligence from Sproles, the fantastic one, and someday replace Sproles when the veteran leaves the game?

"I'm always the most confident player on the field," Pumphrey said. "That's the way I play. It doesn't matter about my size or any of that. I'm out there making plays, no matter what level I'm playing. This is just the next challenge for me."