The Eagles have a running back void that just fits Wendell Smallwood | Marcus Hayes

The return of LeSean McCoy on Thursday only underscores the void he left behind.

McCoy is, arguably, the greatest back in Eagles history, but he wasn't quite Chip Kelly's cup of tea, so Kelly in 2015 punted Shady north, to Buffalo, and replaced him with the spectacularly mismatched combination of DeMarco Murray and Ryan Mathews. That move sped the departure of Kelly himself, with Murray hot on his heels. Now that Mathews' tenure has ended in predictably injury-addled fashion, the Eagles can resume their search for their next backfield hero.

No town reveres runners as Philadelphia does. Mentions of Steve Van Buren, Timmy Brown and Wilbert Montgomery come with hushed reverence. The skills and talents of Ricky "For who? For what?" Watters and Shady McCoy, who both created complicated legacies, generally absolve them of whatever sins they might have committed. Want to guess how many times the Eagles sent  warrior back Duce Staley to the Pro Bowl? Zero. It was part of an eight-year Pro Bowl eclipse between Watters and Brian Westbrook, which was preceded by a 16-year drought between Montgomery and Watters.

For the first time in a long time, there is no backfield hero on the horizon. Mathews, once a Pro Bowl player in San Diego, was released Tuesday when he finally got healthy enough to cut. That left an eclectic group of runners, three of whom seem limited: aptly named bludgeon back LeGarrette Blount, who, at 30, is a well-worn, one-year Band-Aid; Darren Sproles, 34, a Mighty Mouse of a man likely riding in his last rodeo; and fourth-round rookie Donnel Pumphrey, Sproles' understudy, who lately is afflicted with a case of dropsy. Then there is Wendell Smallwood, a Wilmington, Del.,  native and an Eagles fan who comes with no qualifiers. He is the only one among them whose measurements and talents really fit the job description.

The Eagles need Smallwood to win the job, beginning Thursday night, against the Bills.

Understandably, bigger names — receiver Alshon Jeffery, guard Brandon Brooks and cornerback Ronald Darby — have received plenty of anxious attention as to their inclusion in a relatively meaningless preseason game Thursday. Injuries might further delay the 2017 debuts of Jeffery and Brooks. Darby switched cities with Jordan Matthews just this week, so he might not be up to speed. That trio is considered part of the blueprint for the foreseeable future.

[The many Eagles-Bills connections entering Thursday's preseason game.]

Smallwood is still in the middle of a long audition.

He suffered a hamstring injury that cost him the Eagles' first preseason game, last week in Green Bay. In his absence, the team seemed to abandon its run game altogether. Head coach Doug Pederson called just 19 running plays, which totaled 47 yards. Yes, the team was behind; and yes, the Packers blitzed more in that single preseason game than most teams blitz in any two regular-season games. But remember, this is preseason. Winning games is irrelevant. What is relevant is establishing an identity, establishing cohesion, establishing who, among four candidates, is the featured back.

"The plan would be to try to get [the run game] established a little bit this week and see where it goes," Pederson said Tuesday. "I really feel like we've got a good offensive line that can handle that with the backs that we have. It's something that we'll try to focus on hopefully Thursday."

[Eagles can finally stop pretending Ryan Mathews will be on this year's team]

Pederson wouldn't commit to Smallwood's playing Thursday, and, certainly, Smallwood shouldn't play in the second preseason game on Aug. 17 if it will compromise his availability for the opener Sept. 10. But the Birds have to know about him sooner than later.

He plays a position in which diamonds can emerge from the second and third days of the draft, and, last season, Smallwood, a fifth-round rookie, showed flashes of being the latest late-round steal. He produced when given the chance: In a 10-game stretch, Games 2-11, Smallwood gained 289 yards on 65 carries (4.45 average), caught six passes for 55 yards; and returned a kickoff 86 yards for a touchdown at Washington. At 5-10 and 208 pounds, Smallwood showed glimpses of NFL proficiency. Then he sprained his right knee in Game 13 and went on injured reserve.

His importance to the team as it is constructed cannot be overstated. Sproles is a boutique player. Pumphrey is too small. Blount is too worn down. It is too much to expect undrafted free agent Corey Clement to elevate himself above the practice squad.

Second-year quarterback Carson Wentz needs Smallwood. Pederson needs Smallwood.

Philadelphia needs Smallwood.