Doug Pederson, not long after he was named Eagles head coach, did his part to help save the endangered position of fullback when the Eagles signed Ryan Mueller to a two-year contract in April 2016. But Mueller’s tenure lasted only 32 days, and the Eagles haven’t had a fullback since.

While Andy Reid still keeps a fullback on his Chiefs roster, despite the many spread concepts he has adopted, Pederson decided three years ago that a fullback was no longer a necessity in the offense he had taken from his mentor.

There are various reasons for the decreasing use of the NFL fullback, but the speed of the modern game might be the most prominent explanation for why a dozen teams didn’t even fill the position last season. It’s not so much that fullbacks lack the necessary speed, but why have one on the field when there’s a quicker receiving option on the bench?

Speed has always been one of the fundamental components of successful football players and teams. But the changing nature of the game, with the way the league has limited defensive contact and the way offensive coaches have taken advantage, has placed a greater emphasis on finding sprinters and those who can cover them.

“It’s almost killed the fullback position. So it’s, ‘Let’s get another speed guy on the field,' ” Reid said recently. “It doesn’t work logically, but it does on the football field. Even though defenses are more creative with their blitzes, offensive guys are more apt to scat, release, and run [the running back] and just get him out of there and just say the quarterback has another guy to throw to.”

The Eagles could use a skill-position player with that kind of dynamic speed, whether it’s a running back with ball-catching ability or a receiver who can run with the ball. The return of DeSean Jackson should give the Eagles the vertical element they’ve been lacking since he left five years ago, but the 32-year-old wide receiver is no longer the dual threat he once was.

There are serviceable options on the roster. Receivers Alshon Jeffery and Nelson Agholor have had varying degrees of success with jet sweeps and bubble screens, and running back Corey Clement has flashed as a receiver (see: Super Bowl LII). But there isn’t a two-way player who is a consistent home-run threat.

Of course, there are only so many Tyreek Hills or Alvin Kamaras in the NFL. Nearly every team is looking for a game-breaker. But that shouldn’t stop the Eagles from trying to acquire one. The coming draft offers some compelling candidates who could fill the need for players who can play in space.

“You’ve seen a lot of those spread concepts come up to the professional level,” Eagles vice president of player personnel Joe Douglas said Tuesday. “There’s been a lot of discussions about, for lack of a better word, position-less players. Guys that you can move around in different formations, but not only offense, but also defense.”

Pederson has been flippant this offseason when asked whether he felt the Eagles needed to add young speed on offense, particularly at running back. Jordan Howard, acquired in a trade last month, is still young at 24, but he’s neither fast, relatively speaking, nor particularly dangerous as a receiver. But, his addition doesn’t preclude the Eagles from expending a draft pick on a running back.

If they’re open to the possibility of a Day 2 selection, Darrell Henderson could be the prospect who qualifies most as a dynamic running back. He’s not exactly a burner, but he ran a respectable 4.49 40-yard dash at the combine and, at 5-foot-8 and 208 pounds, had an elusiveness at Memphis that helped him average 8.9 yards per carry over his last two seasons.

The Eagles struck out the last time they took a productive college running back from a smaller conference, but Donnel Pumphrey’s struggles to integrate into the NFL shouldn’t be used against Henderson.

Stanford’s Bryce Love regressed in his senior season and suffered a torn ACL in his final regular-season game, but the 5-9, 200-pound former track star could be a Day 3 alternative if the Eagles are willing to wait until he’s completely healthy.

Neither Henderson nor Love caught many passes in college, but neither did Darren Sproles, one of the NFL’s best receiving tailbacks of the last decade. What players such as Sproles, who recently said he would decide on his future after the draft, increasingly offered to offensive coordinators was the option to send five receivers into routes.

“Defensive coordinators have gotten so good at all their different things, the combinations they do, including linebackers and twists with the defensive line," Reid said. "Secondary people are in the mix: corners, safeties. So you say, ‘OK, let’s spread them out where it declares,’ and then just say, ‘You got to be good enough to cover each one of these skill guys right here.’ And then have the quarterback get the ball out of his hand.”

With Carson Wentz at quarterback, the Eagles increasingly went with an empty backfield when they had the matchups they wanted, whether against a base or big-nickel defense. Agholor has after-the-catch talents, but he’s entering the last year of his rookie contract, and his replacement might be in this year’s draft class. Oklahoma’s Marquise Brown, South Carolina’s Deebo Samuel, and Ohio State’s Parris Campbell all thrived in space and could be explosive weapons for spread-conscious NFL offensive coordinators.

“Coordinators are stretching you now horizontally and vertically,” Raiders coach Jon Gruden said. “They make you defend every blade of grass. Jet sweeps, you got to have guys who can run that down. You got to have guys who can make open-field tackles. Just the bubble screen itself, who’s making that tackle? Guys got to play in space more than they ever have before.”

The two defensive positions that have probably been affected the most by the offensive evolution have been safety and linebacker. And to account for the speed quotient, coaches have increasingly turned cornerbacks into safeties and safeties into linebackers. Some might have positional titles, but they’re hybrid players with the versatility to match up against receivers, running backs, and tight ends.

“There are some tight ends that have length and size, and who can have the size and length to match up with them? There are some running backs that can move and change directions the way that Sproles can change direction — that’s a tough matchup,” Falcons coach Dan Quinn said. “So, when you’re evaluating the players, whether it’s free agency or in college, you better have a good vision of what that guy would do for your team.

“I see him being able to play this position, playing over tight ends, or at this position [that] he can guard the running backs. Not everybody can do all of those roles. So, having players that can defend different styles of players, I think that’s really important.”

The Eagles, despite their need for linebackers, are unlikely to expend a first-round pick on a top prospect such as LSU’s Devin White and Michigan’s Devin Bush. But both qualify as the new breed of smaller sideline-to-sideline defenders. The Falcons’ Deion Jones, whose size (6-2, 220 pounds) might have made him a box safety 25 years ago, was chosen in the second round three years ago. He probably would go one round earlier now.

“He’s not the biggest of guys, but he can fly,” Eagles tight end Zach Ertz said. “And he’s a guy you really have to account for on the back side of the running game, because he is so fast that sometimes he just outruns the angles that you have from an offensive standpoint.”

Ertz said that the NFL’s pendulum could swing back toward a game built more on power, and, like others this offseason, pointed to the Patriots’ ground-and-pound success against the Chargers in the playoffs.

“This game, as in life, is cyclical,” Ertz said. “So, we’re going to get a ton of linebackers that are flying like this, and then there’ll probably come a point in time, like the Patriots did against the Chargers in the playoffs last year, where they just ran the ball for 250 yards in a game because they had seven DBs on the field.”

But that was likely an anomaly, simply a better coaching staff taking advantage of the ineptness of another. Unless the league suddenly scales back on two decades’ worth of restrictions on hitting, speed will continue to trump strength in the NFL.