The ball sails through the crisp fall air, turning end over end as Darren Sproles calmly tracks it and positions himself beneath its arcing trajectory. Catching the punt cleanly, he makes his first move, a burst of speed straight ahead as he recklessly sprints directly toward a pack of advancing defenders. One of his blockers gets out in front and opens up a lane for the Pro Bowl return man, who quickly changes directions to avoid the pileup. After leaving two more defenders in his wake, he barrels up the sideline with just the punter left to beat. He cuts back toward the middle of the field, where he zips by him and takes it all the way to the end zone as a loud air horn sounds.

It's a Friday afternoon walkthrough, and while most of the players on the field are, well … walking through the drills, the 32-year-old running back is darting all over the field, pounding his cleats into the turf and sprinting up until the whistle during each and every drill. Head coach Chip Kelly believes that the pace at which players practice dictates the pace at which they play on gamedays, which would explain why Sproles often spends his Sundays making opposing defenders look silly.

"I've never been around a guy – and I've been around a lot of guys – that practices as consistently hard as Darren does every single day," Kelly said of the 2014 Pro Bowl selection, whose versatility as a rusher, receiver and punt returner makes him one of the most dynamic weapons in the league. "Early, you're trying (to tell him), 'Hey, you've got to (slow down).' Doesn't matter. If we have a walkthrough punt, he's going to catch a punt and run 60 yards with it and try to score a touchdown."

Sproles has always played with that mindset, not only out habit but out of necessity.

In a game designed for giants, he stands a meager 5-6, making him the shortest player in the NFL today along with Chicago running back Jacquizz Rodgers. But Sproles actually believes that his height helps him more effective, not only because it lowers his center of gravity and makes him more difficult for opposing linebackers to spot when he runs between the tackles but also because it's forced him to consistently outwork everybody else simply to prove he belongs.

When he was 9 years old, his father, Larry, signed him up for pee-wee football in their hometown of Olathe, Kansas. Despite being a head shorter than just about every other kid on the field, he was so dominant with the ball in his hands that the league actually barred his team from running Sproles outside the tackles. He scored at will anyway and was forced to transfer to an inner-city league about 30 minutes north, in Kansas City. The children he played against there were older, and significantly bigger than him, but his speed still made him virtually unstoppable, as it did in junior high and high school as well.

As a senior at Olathe North, he rushed for 2,485 yards and an unfathomable 49 touchdowns while leading the school to a 12-0 record and a state title. Still, his height dissuaded college recruiters from taking his accomplishments seriously, and he garnered only moderate attention before eventually committing to nearby Kansas State. He finished his career with the Wildcats sixth all time in the NCAA for all-purpose yards, breaking 23 school records along the way. Last month, Sproles' named was added to Kansas State football's Ring of Honor.

Still, it wasn't enough.

Sproles remembers being told by NFL scouts that if he had been just a few inches taller, he'd have been a lock to go in the top five of the NFL Draft. Instead, he fell to the fourth round, where the San Diego Chargers made him the 15th running back selected in 2005. In the 10 years since, he's made it his mission to prove wrong each and every one of the coaches, scouts and executives who labeled him "too small."

It's that drive that's made him one of just six players ever to reach 17,000 all-purpose yards in their first 10 seasons. And it's his commitment to overcoming the perceived physical limitations with which he was born that has allowed him to maintain his impressive production at an age at which many running backs have already broken down

"The guy trains so hard, not only during the season but in the offseason as well," said tight end Zach Ertz, who spent this past offseason working out with Sproles in San Diego. "He's so consistent in everything that he does, both on the field and off, and he pushes everyone he works with to be the best that they can be as well."

One Eagle who has benefited tremendously from the mentorship of Sproles has been running back and punt returner Kenjon Barner, a former standout at Oregon who fell to the sixth round of the 2013 Draft in part because of his 5-9, 185-pound frame. The 26-year-old collegiate track and football standout looks up to Sproles, not only because of the guidance he happily offers but because of the example he sets every day.

"I couldn't ask for a better blueprint to be laid out before me," said Barner. "He's done everything that I hope to accomplish in my career and more, and he's taught me a great deal about the game and about life. From a punt return perspective, he changed the way I approach it, the way I look at it, how I prepare for it."

Barner remembers warming up before the Eagles' preseason opener against Indianapolis this year and noticing that Sproles wasn't fielding any practice kicks from punter Donnie Jones. Instead, the veteran back was simply standing off to the side of the field and watching Colts punter Pat McAfee warm up. A few minutes later, Sproles approached Barner and sternly told him, "You need to be over here with me, not catching balls from Donnie." Barner looked confused, so the veteran continued, "When the game starts, you're not going to be catching balls from our guy, you're going to be catching balls from their guy, so go watch how he kicks it."

"He completely changed the way I look at the game," said Barner, who went on to return two punts for touchdowns during the preseason, including one against McAfee and the Colts. "Now, I catch a few punts from Donnie before games, but then I just watch the opposing punter – how his ball drops, the kind of spin he's getting on it, whether it's end over end, high, low, long, short, because he's going to practice it exactly the way he's going to do it in the game. … I was out here thinking preparation is Monday through Saturday, and he was still preparing pregame on Sunday, and that really opened my eyes."

It's that intersection of natural-born talent and uncompromising preparation that makes Sproles such a dynamic threat whenever the ball is in his hands. Since joining the Eagles in 2014, he's scored 10 touchdowns in 19 games played, including three on punt returns. And more often than not, his scoring plays have come when the team has needed them most. Seven of his 10 touchdowns over the past two seasons have come while the Eagles and their opponent were within seven points of one another, and Philadelphia boasts an 8-2 record when Sproles scores at least once. For the Eagles, the shifty veteran is often the spark that ignites the entire team, and there's a sense of anticipation on the sidelines whenever he has the ball in his hands with room to run.

"There are a couple of things that are guaranteed when he catches the ball," explained safety Malcolm Jenkins, who's played alongside Sproles in each season since 2011, when the two were teammates with the New Orleans Saints. "The first guy's going to miss. And then, if you can get a hat on everybody else, he's going to score.

"He's probably still the best returner in the game right now, and I don't see that changing."

This story appears in the Saints vs. Eagles edition of Gameday Magazine, which will be available at the Lincoln Financial Field Pro Shop and at participating ACME Markets.