If you thought the Eagles played it fast in the first two seasons of the Chip Kelly Era, well, the idea is that there is another gear to hit. And to hit that gear, the Eagles need to roll through their running backs, and to have a three-pronged attack featuring DeMarco Murray, Ryan Mathews and Darren Sproles is absolutely ideal.

On a remarkably huge Thursday at the NovaCare Complex that featured four press conferences, two new running backs and a helicopter's television footage tracking one of those back's trip from the airport to the facility, the Eagles completed – maybe? – their overhaul of the offensive backfield.

They signed running backs DeMarco Murray, who led the NFL in rushing as a member of the Dallas Cowboys in 2014 and then became the first player since 1947 to change teams for the next season – to a hated division rival, of course – and Ryan Mathews, who ran for 4,061 yards (averaging 4.4 yards per carry) in 60 games with the San Diego Chargers.

Those two, along with Pro Bowl running back/return man Darren Sproles, give the Eagles an unprecedented depth of talent in the backfield and stoke the fires for Kelly's imaginative use of personnel. The Eagles also have Chris Polk, a power back who has been tendered a one-year deal as a restricted free agent, along with Kenjon Barner and Matthew Tucker, both of whom spent time on the practice squad here in 2014.

It's a dramatic turnover from last year when LeSean McCoy gained 1,319 yards on 312 carries and played 775 of the offense's 1,176 snaps (66 percent) as he became the franchise's all-time leading ground gainer. McCoy was traded to Buffalo in exchange for linebacker Kiko Alonso on the first day of free agency and the Eagles swiftly went about the process of revamping their running back picture and, likely, their approach to how to use their backs.

The idea, it appears, of a single-back-dominated ground game is in the past. Kelly wants to run the football; the Eagles led the NFL in rushing yards in 2013 and gained 1,992 yards in 2014 as McCoy finished third in the league in yards.

By stocking the cupboard with talent – and both Murray (2013 and 2014 seasons) and Mathews (2011 season) have been in the Pro Bowl – Kelly has more options. Murray (217 pounds) and Mathews (220 pounds) can bring it with their one-cut-and-go style and Sproles is the killer in space. How Kelly uses the three backs remains to be seen. He certainly is going to have fun designing X's and O's and moving pieces around and keeping his backs fresh.

Imagine, if you will, the backs rotating in the course of games and wearing down defenses and pounding away on the ground. The Eagles averaged 73.5 offensive snaps per game in 2014 and they want to go fast, faster, fastest this season. They want 80 snaps. They want the backs to run north-south. They want to create matchups that defenses can't handle.

And by having two backs with size and physical running styles, they want to be far, far better running the football in the red zone than they were last season when they scored touchdowns on 49.2 percent of their red-zone chances (ranking 23rd in the NFL). The year before, despite leading the league in explosive (plus-20 yards) plays, the Eagles converted just 52.3 percent of their chances (ranking 13th in the NFL) inside opponents' 20-yard line.

Murray was sensational in 2014 with 1,845 yards and 13 touchdowns on 392 carries. He added another 57 receptions and 416 receiving yards. He was a force as Dallas won the NFC East and a postseason game. He is reunited with his roommate at Oklahoma, new Eagles quarterback Sam Bradford, as Kelly makes over the entire offensive backfield. Murray is the headliner here and he's going to get his touches.

But he's not going to get 448 touches in 2015. There's no way a running back can withstand so much work two years in succession. Mathews and Sproles are here to take some of that work and do their damage and keep Murray as fresh in December and January and February – we hope! – as he is in September.

Mathews missed 18 games in his time in San Diego with a variety of injuries, so he's got to dig in deep with the Eagles' sports science program and also hope for a little bit of luck. Same with Murray, who played in 16 games in 2014, his first season playing every game. 

The talent is certainly tantalizing and Kelly wants to use every bit of it from all three players who have similar skill sets in that they are all versatile, and physical, and extremely capable in the passing game. The head coach is acutely aware of the injury factor, too, so he's not going to overwork and wear down any of the three.

Murray will get his runs and catches. Who knows? Are 20 touches a game enough to keep Murray fresh? Start there and then use Mathews for 6-8 touches and give Sproles some work in the backfield and in the return game and each of those three will be happy because the Eagles will have success.

This is not to suggest that the offense is finished. The Eagles have work to do along the offensive line and at wide receiver. But in a very short time, they've re-signed Mark Sanchez and traded for Bradford at quarterback and signed Mathews and then Murray for the deepest group of running backs in the entire NFL. The three-headed monster the Eagles used in 2003 with Brian Westbrook (613 yards), Correll Buckhalter (542 yards) and Duce Staley (463) helped take the Eagles to the NFC Championship Game, and it was very talented and the three worked well together.

This model has more rocket power, more juice. The offense's strength starts in the backfield, where the possibilities are endless. You know that Chip Kelly, who has a mind that doesn't stop seeing new angles, is working on ways he can maximize the might he has in a backfield that has it all.