THERE WAS a moment a couple of weeks ago during an 11-on-11 period that made you stroke your chin a bit. Darren Sproles, isolated on a linebacker on the right side of the formation, took a couple of steps and busted a slant across his defender's inside shoulder for an easy catch-and-run in the middle of the field.

It was the kind of play we have seen throughout the career of the little two-legged hovercraft, and you couldn't help but wonder if it was something that Chip Kelly decided he was going to need to see more of after Jeremy Maclin signed with the Chiefs in March. In fact, as assumptions go, it is a pretty safe one. The Eagles made a concerted effort to sign Maclin, which means they thought they would be a worse team without him, and the only moves they made to address his departure were the signing of Miles Austin and the drafting of Nelson Agholor, which means they'll need to find the rest of the missing production somewhere else on the roster. And they just might find it in Sproles.

Kelly raised some eyebrows with his decision to add both DeMarco Murray and Ryan Mathews to a backfield that already included Sproles, but think about it from a different perspective. Perhaps Mathews was signed to effectively replace Maclin, by freeing up Kelly to utilize Sproles as a receiver, similar to the way the Patriots deployed Shane Vereen the last two years.

When you watch the film from last season, one thing that jumps out is how little time Sproles and McCoy spent on the field together. In fact, of the 343 snaps that Sproles saw, just 39 of them came with McCoy also on the field. That's not even three snaps per game. The reality is that Sproles played more of a supplementary role than the complementary one in which he has thrived throughout his career. The vast majority of his snaps came out of single-back sets in which he was the lone back on the field.

Everything that Kelly has said and done this offseason suggests that a lack of depth prevented him from creating the kind of matchups that Sproles can exploit, particularly from within the framework of a two-back personnel group, which forces a defensive coordinator to decide between erring on the side of the run with a base-package linebacker or the pass with an extra defensive back.

"Football is about matchups," said safety Malcolm Jenkins, who spent three years watching Sproles wreak havoc on defensive schemes when they were teammates with the Saints, a stretch when Sproles caught at least 70 passes for 600 yards each season. "You talk about somebody like Darren Sproles, you put a linebacker on him, he's probably more athletic than your linebacker, and if you take a DB and put him on him, then somebody else has a better matchup, whether it be Zach Ertz or one of our slot receivers. You can't put all DBs on the field, because then we will just run the ball. The more players you have that can do more things, the better off you are and the bigger advantage you have."

This year, the Eagles have three running backs who have caught 50 passes in a season, and all three are just as capable of serving as the primary ballcarrier on any given possession. Say you are a defensive coordinator, and you see the following players running onto the field for a play: Murray, Mathews, Sproles and two receivers to go with the offensive line and quarterback. If a strong safety marks Sproles, you can take him out of the play by running to the opposite side. If a cornerback marks Sproles, you can run against nickel and still have a blocking back. And if a linebacker marks Sproles, you can pass on him.

"I think there is going to be a lot of stress in the middle of the field, to be honest," Ertz said. "With the threat of running the ball and then with a guy like Darren out of the backfield or DeMarco or Ryan, it's going to be fun for the offense as a whole."

That wasn't the case last year, when Sproles spent most of the season as the primary backup to McCoy, and was the more effective runner for a considerable portion of it. Then there were those puzzling stretches in game when McCoy would be on the sideline with Sproles taking all of the reps. All of it combined to limit the opportunities to move multiple running backs around the formation to create mismatches on linebackers.

"For us, especially in the beginning of the year, [Sproles] was our only other running back," Kelly said before this year's draft. "So when you try to move him around and put him in a lot of different spots you're kind of holding your breath . . . That's why our goal in this offseason, if we moved LeSean, was that we wanted to bring two guys in and we wanted to have some depth at the running-back spot and possibly carry four guys during the season. There's a lot factored into that, but I think obviously in Year 2 we have a lot more familiarity in what we're doing and in getting acclimated more we need to get [Sproles] on the field more."

Who will replace Maclin at wide receiver? It might be a running back.