PHILADELPHIA -- Opposing defenses might want to buckle their chin straps extra tight when facing the Philadelphia Eagles.

On Tuesday, the No. 4 rushing team in football added the 5-foot-11, 215-pound Jay Ajayi, acquired from the Miami Dolphins in exchange for a 2018 fourth-round pick. He joins a backfield that to this point has been led by the 6-foot, 250-pound LeGarrette Blount.

Philly now has two of the top bruising backs in all of the NFL. According to Pro Football Focus, Ajayi ranks first (81) and Blount third (69) in most forced missed tackles since 2016. That's some serious force lining up behind MVP candidate Carson Wentz.

The question becomes: How will the pairing work? Both are at their best when being fed the ball regularly. There are not enough carries to go around to keep both satiated in that way.

Blount is almost certainly the one who will have to make due with less. You don't give up a fourth-round pick for a 24-year-old coming off a Pro Bowl season and relegate him to the sideline for long. Ajayi is viewed as an upgrade in pass protection, and coach Doug Pederson could lean on him over Blount in passing situations as well.

Ideally, the Eagles would have acquired a back with third-down expertise who could be the lightning to Blount's thunder. But the market bears what it bears, and there's little doubt that Ajayi will make this offense better if he can find something close to his 2016 form.

Pull the lens back and the trade makes more sense. Though there is some positional-skill overlap with Ajayi and Blount, only one is under contract past the 2017 season. Blount, 30, is on a one-year deal, and Ajayi's rookie contract runs through 2018. Executive vice president of football operations Howie Roseman wants young players who will be alongside Wentz for the long haul. Though there are some health concerns, Ajayi could be one of those core players moving forward if the body holds up.

And he is more than just a physical back. Ajayi had 10 runs of 20-plus yards last season -- four of which went for 40 yards or more. He adds a game-changing element that wasn't present in the backfield before the trade.

There are some concerns here. His output has dropped off to this point in the season. According to ESPN's Jeff Darlington, the Dolphins traded Ajayi because they believe his most productive games are behind him, fearing the knee issues stemming from a significant 2011 surgery are finally catching up to him. It's to be determined whether he will prove them wrong. And there's a chance Blount becomes less effective while the biggest need -- pass protection -- remains a question mark.

There is also potential. Blount is coming off a year in which he led the NFL with 18 touchdowns, and Ajayi ran wild to the tune of 1,272 yards (4.9 average) and eight scores. If they can find a way to co-exist, defenses will have to absorb wave after wave of punishing runs for four quarters. That could serve the Eagles well late in games, and late in the season, as opponents wear down.