Editor's note: The Buffalo Bills will release veteran running back LeSean McCoy, sources told ESPN's Adam Schefter on Saturday morning. This story was published prior to the news.

ORCHARD PARK, N.Y. -- There's never been a backfield like the one the Buffalo Bills will likely roll out in 2019.

Let that soak in.

According to the Elias Sports Bureau, never in NFL history have two players with at least 10,000 rushing yards each played in a game for the same team. If LeSean McCoy and Frank Gore suit up against the New York Jets in Week 1, the Bills will be the first.

What they do with the historic backfield remains to be seen, but general manager Brandon Beane said before the team began training camp last month that McCoy "is going to be the first running back to touch the ball." However, the preseason offered little clarity as to how he and Gore will split the workload -- especially with rookie Devin Singletary's emergence as a potential playmaker.

Offensive coordinator Brian Daboll has led several talented backfields during his 18 years in the NFL. He's been a O-coordinator for the Browns (2009-10), Dolphins (2011), Chiefs (2012) and Alabama (2017) before returning to the NFL with the Bills last season. Twice, his backfield featured two players who recorded at least 140 carries.

Jerome Harrison and Jamal Lewis finished the 2009 season with 194 and 143 carries, respectively, as the Browns ranked eighth in the NFL in rushing yards and sixth in attempts. Reggie Bush and Daniel Thomas carried the ball 216 and 165 times, respectively, with the Dolphins in 2011 -- who ranked 11th in the league in rushing yards and sixth in attempts.

Daboll wasn't ready to compare the Bills' backfield to any other one he's coached, because he's still learning exactly what he has this season.

"Each year is such a different year," Daboll said. "The preseason and training camp are meant to get acclimated to one another and really, until you get out there and the bullets are flying, so to speak, in the regular season [you don't know for sure].

"This will be my 19th year in the NFL. I've been around a lot of good coaches, a lot of good players and the one thing I've learned is each year is so different from one to the next -- but you can lean on past experiences."

In the only preseason game that both Gore and McCoy were active, they split carries -- eight attempts for Gore, six for McCoy -- for 57 and 37 yards, respectively. Daboll said practice and game performances "will all determine what we do and what we don't do," but it does feel like a near-even split is more likely than not.

"These are unique situations where you are able to have two running backs like we do, with their ability and the amount of football that they have seen," Bills coach Sean McDermott said. "Those two guys, Frank and LeSean, have been truly consummate pros as they’ve handled it. I think you've seen some of the results of it the other night -- the way we are able to run the ball and run the ball effectively."

Though their career numbers speak for themselves, Gore and McCoy are closer to the end of their careers than the beginning. McCoy, 31, set career-lows in 2018 in rushing yards, yards per game and yards per carry.

Gore, 36, was still effective in 2018, recording the fifth-highest yards-per-carry mark of his 14-year career, albeit on his second-fewest attempts per game. He's been remarkably healthy, playing in 210 of 224 possible regular-season games, but conventional wisdom speaks against overworking the man who ranks No. 5 in career carries.

"Frank Gore is a true pro, man. Everybody can learn a lot from Frank Gore -- not just players, but the coaches," Daboll said. "What you don't know, not being around him, is the type of person he is, how much he loves the game of football, the preparation process, how he takes care of his body. He's a really good veteran."

Of course, the Bills might not have to worry about putting too much on their veteran backs if the early returns from Singletary's training camp translate to the regular season.

The 2019 third-round pick was a prolific runner in three seasons at Florida Atlantic, rushing for 4,287 yards and 66 touchdowns in three seasons. Singletary also caught 51 passes, 26 of which came during his freshman season. But Daboll lined him up all over the field during training camp, hinting at a bigger role in the passing game than his collegiate numbers suggested.

"I saw him as a good player. He didn't get many opportunities in the passing game (at FAU) ... We did a lot of work on him," Daboll said.

The Bills ranked ninth in the NFL is rushing yards last season, thanks in part to quarterback Josh Allen's historic rushing output, which led the team. But Beane, McDermott and Daboll are hoping a strengthened and more diverse backfield allows Allen to lead this offense with his arm instead of his legs.

And it doesn't seem like Allen is complaining.

"With the knowledge that Frank has -- and he can still play and still run. With how explosive Shady [McCoy] is, and Motor [Singletary] with what he can do in the passing game as well in the running game -- I think it adds a lot of different elements," Allen said. "There's guys that can do different things. It's fun to watch. It's kind of cool how they communicate and how they try to develop their skills, kind of leaning on each other for advice and mental reps.

"I've seen how Shady does it and especially Motor, he's in a great position with two great running backs in front of him like that. To learn from them and see their body language and how they kind of go through daily NFL life -- it's awesome."