The only certainty on an NFL roster from one season to the next is that the players must view their seats at the table with varying degrees of uncertainty.

A year ago, as the Eagles were rolling toward a high seed in the NFC and a possible championship push, it was accepted that if they were successful, many of the teammates who made it possible would not return to attempt a repeat performance. That played out, of course, and 16 players who were on the 53-man roster for the Super Bowl were gone from the organization when the Eagles came out of the tunnel for the season opener this year.

In the same way, as the team tries to hold itself together this season with the odds against it, there are just as many players who might be jettisoned after failure as there were after success. Maybe more, because while nostalgia follows a parade, a flop is followed only by the street sweepers. The Eagles, still cap-strapped from their machinations to draft Carson Wentz, will also need to tighten their belts further as the quarterback’s inevitable contract extension becomes a reality.

With that as a subtext, it was poignant to see center Jason Kelce and former tight end Brent Celek in close conversation after Monday night’s game against Washington in the victorious locker room.

Kelce, who has played 110 games for the Eagles since being drafted in the sixth round in 2011, is in perhaps the same position Celek was a year ago. He is a veteran over 30 years old, and the terms of his contract make it advantageous for the team to consider another direction next season.

That won’t definitely happen -- Kelce is still playing at a high level -- but his name is on a list of current Eagles who might well become former Eagles for reasons that involve the salary cap as much as anything else.

Put Darren Sproles, Mike Wallace, Jason Peters, and Corey Graham on the list, too, and throw in Ronald Darby, Jordan Hicks, Michael Bennett and Rodney McLeod. The front office will have to make tough decisions, as it does every offseason, but if they are made in January as opposed to February, the torrent of falling confetti won’t be a distraction from the cold task.

Kelce, who will turn 32 next season, is in an odd spot. He has always been small for his position, and struggled badly as he transitioned from Chip Kelly’s sprint-out offense to the more stay-at-home philosophy of Doug Pederson.

He rebounded to play extremely well last season, and this year, despite playing on aching knees and overcoming a midseason elbow injury, he has been very good. His highlight for the season came against Washington, when he led Sproles downfield, sealing off a potential tackler with one arm before turning his attention to another defender near the goal line. It was the kind of play in the open field that few offensive linemen can make and resulted in a touchdown for Sproles.

“That’s why I play in the NFL. I’m pretty good at stuff like that,” said Kelce, who is always clear-eyed about what got him here and what, if anything, will keep him in uniform.

Kelce’s longevity has been remarkable, although teams tend to leave the center alone when they find one. The two regular centers prior to Kelce (among players who started at the position for more than two years) were Jamaal Jackson and Hank Fraley, and that trio of centers stretches back a full 18 seasons.

Since Kelce last missed a game – he was out four games with a hernia strain early in the 2014 season – he has started 69 consecutive regular-season games and three postseason games, and been on the field for 4,998 of 5,103 offensive snaps. Only safety Malcolm Jenkins has a longer streak on the Eagles (75 regular- season games) and, among NFL centers, only Ben Jones of Tennessee has gone longer without missing a start (108 games).

While Kelce has been a constant in the middle of the line during his streak, he has taken his position shoulder to shoulder with guards Todd Herremans, Matt Tobin, Andrew Gardner, Evan Mathis, Allen Barbre, Brandon Brooks. Isaac Seumalo, Chance Warmack, and Steve Wisniewski.

This season, even though the personnel has been fairly static, the line has had its problems. Part of that is due to injuries to running backs Sproles and Jay Ajayi. Part is due to the way games have gone, dictating that the Eagles be obvious in their need to pass. There was improvement in back-to-back wins over the Giants and Redskins, but the Cowboys bring a tougher challenge on Sunday. To be blunt, this game will show whether the improvement was real or illusory.

“We knew we had to beat the Redskins, but we’ve also got to beat Dallas. Unfortunately, we put ourselves in this position,” Kelce said. “We weren’t in sync early on and now it feels like we’re starting to hit our stride. I think it’s more about timing this year. We had a shortened offseason, and a quarterback who missed the entire offseason, and a left tackle coming off ACL surgery, guys who had late-season injuries. It was a lot of pieces and it’s been tough from a chemistry standpoint. We’re starting to do better.”

The Eagles are guaranteed only four more games this season, and Kelce is guaranteed only four more in his career with them. Both the team and the player can still earn bonus time. It could be this season will be remembered as fondly as the previous one. That’s uncertain, but every season ends with uncertainly, some earlier than others.