In a league increasingly reliant on the passing game, the Kansas City Chiefs have stuck with the old school football philosophy based on a strong defense and running game.

Of course, more goes into it than just the philosophy, but over the past few years, the Chiefs have had the defense and running game to pull that type of strategy off.

By our Net Expected Points (NEP) metric, Kansas City excelled in both areas during 2015. NEP, by the way, measures the value of each play on the field based on how an average team would be expected to score in each scenario using historical data.

The Chiefs were seventh in Adjusted NEP on defense and second in Adjusted Rushing NEP on offense. The defense has the likes of Justin Houston, Derrick Johnson and Eric Berry, while the running game had been carried by Jamaal Charles.

But behind Charles over the past few seasons have been slew of running backs ready to spell him when he came off the field. Heading into the 2015 season, that backup was perceived to be Knile Davis. Davis had 134 carries behind Charles in 2014, but those were some of the 134 least efficient carries in football that year.

In 2014, 43 running backs carried the ball at least 100 times, and none had a worse Rushing NEP per attempt than Davis’ -0.16. Charles, meanwhile, led all backs that year with a Rushing NEP per attempt of 0.11.

It would be of little surprise, then, when Charles was lost for the season after tearing his ACL in Week 5 that Davis was not first in line to fill for Charles as the lead back. Instead, that duty was split between Spencer Ware and Charcandrick West. The work both did in 2015 has led to the Chiefs handing out identical two-year, $3.6 million contract extensions.

Ware and West

When Charles was lost for the year, West was the first to step in with some mixed results. West’s first game without Charles saw him carry the ball nine times for 33 yards. He followed that with games of 22 carries and 110 yards and 20 for 97 in back-to-back weeks. West then struggled in the next game, getting only 69 yards on 24 carries against the Broncos.

Ware didn’t get the reins until the next game -- his first game with more than two carries didn’t came until Week 11. But once he got the ball, he put up some of the best efficiency numbers of the season. Ware was fourth in Rushing NEP per attempt among the 82 backs with at least 30 carries during the season. Ware’s production was even better than Charles’ before his injury with a similar number of carries.

Only five running backs were able to have a Success Rate -- the percentage of carries positively impacting NEP -- of 50 percent or greater. Ware was one of those five, along with Mike Tolbert, Ka'Deem Carey, Rashad Jennings and David Johnson.

Splitting Shares

Charles is expected to be healthy and ready to go by the start of training camp in July. While that’s overall good news for the Chiefs, it does potentially limit the amount of touches Ware and West will receive in 2016. But should the load for Charles be decreased, both backs have shown they have the ability to step in and more than competently handle a larger amount of carries.

The way the two backs have started their breakouts, though, has been slightly different. Ware is more of a big play threat, based on his excellent vision and ability to create yards on his own.

Take the following play against the Houston Texans. Ware patiently follows pulling guard Jeff Allen, who helps create a hole in the middle of the defense. Once Ware gets into the second level, he’s able to lower his shoulder, break a tackle and pick up an extra seven yards. (Video courtesy  NFL Gamepass.)

In the next play, against San Diego, Ware is able to avoid a tackle for loss in the backfield, power his way through a cluster of offensive and defensive linemen, emerge out the other side and drag a tackler another four yards before being taken down.

It’s plays like this, taking a possible loss and turning it into a big gain, that boosted Ware’s efficiency metrics last season.

Meanwhile, West’s biggest plays of the season came when the offensive line allowed him to have big plays. This isn’t necessarily a bad thing, because the Kansas City offensive line happens to be pretty good. It also got better during the offseason with the signing of Mitchell Schwartz, one of the best right tackles in the league.

West excelled when holes were made for him, like this run against the Patriots. Kansas City lined up eight blockers along the line of scrimmage with two tight ends and a receiver on the left of the line. Those three are key in creating a wide hole for West to run through for a long gain.

In a game against the Browns, West took a handoff to the outside. He, like Ware in a play above, gets help from a pulling Jeff Allen, who takes out two Browns defenders with a block. West gets a wide open space and an easy gain of 22 yards once he turns the corner.

Moving Forward

Both Ware and West are just 24 years old, which will give them plenty of time to continue to develop into players who can handle bigger loads in the running game -- West turns 25 years old in July, while Ware doesn’t turn 25 until November.

Whether they’ll get a chance to develop this year likely depends on the health of Charles. But Charles will turn 30 years old in December and has no guaranteed money remaining on his contract, which runs through the 2017 season.

With the extensions in place, the Chiefs have already been shopping Knile Davis in a trade, taking away any threat of jumping the other two backs on the depth chart -- though he wasn’t much of threat when he was on the roster in 2015.

Whether this young duo of running backs gets a chance to shine in 2016 or has to wait until 2017, the future of the Kansas City backfield will be in good shape with Ware and West in it.