Ben McAdoo looks against the Oakland Raiders at Oakland-Alameda County...

Ben McAdoo looks against the Oakland Raiders at Oakland-Alameda County Coliseum on December 3, 2017 in Oakland, California. Credit: Getty Images / Thearon W. Henderson

It is impossible to overstate the significance of where the Giants are right now. It is a crossroads moment in club history, the outcome of which likely will determine the team’s direction for years to come.

A confluence of events has taken place during a 1-8 start that ultimately could force changes the Giants haven’t experienced in nearly four decades. Sweeping changes at every level of the football operation, with Ben McAdoo, Jerry Reese and Eli Manning all facing uncertain futures.

Co-owners John Mara and Steve Tisch offered a reprieve Monday, indicating in a statement after a 31-21 loss to the previously winless 49ers that no changes will be made until after the season. “While we appreciate that our fans are unhappy with what has occurred, nobody is more upset than we are,” Mara and Tisch said. “Our plan is to do what we have always done, which is to not offer a running commentary on the season. It is our responsibility to determine the reasons for our poor performance, and at the end of the year, we will evaluate the 2017 season in its entirety and make a determination on how we move forward.”

Despite increasing calls for the owners to part ways with McAdoo, they have given him until the end of the year to prove his case. More likely than not, they will conclude that he is not up to the job and that last year’s playoff run can’t mask the myriad imperfections the coach has shown in a season run amok.

Or maybe they already have decided that to be the case and simply want to finish out the season rather than go with an interim coach simply to appease a frustrated fan base.

A 51-17 loss to the Rams last week followed by another meltdown against a rebuilding 49ers team and a rookie quarterback in C.J. Beathard — games in which the Giants’ effort level was rightfully called into question — likely sealed McAdoo’s fate, and quite possibly Reese’s.

The general manager was put on the spot by Mara before the 2016 season to get his roster in order, and a $200-million free-agent spending spree that landed Janoris Jenkins, Olivier Vernon and Damon Harrison and kept Jason Pierre-Paul from leaving reaped early rewards. But with Jenkins getting suspended for a game after failing to return on time from the bye week, with Vernon missing time with an ankle injury and with Harrison and especially Pierre-Paul underperforming, even that plan is coming apart.

Reese’s inability to adequately address the offensive line also is at the heart of the problems, although left tackle Ereck Flowers appears to have progressed since an awful start to the season.

The chemistry issues afflicting the team can’t be ignored, and the owners could choose to make a clean sweep involving the entire football operation.

The two things that could save Reese: his recent drafting of star players such as Odell Beckham Jr., Landon Collins and rookie tight end Evan Engram, and the possibility that ownership views this year’s debacle as more of a coaching issue than a personnel problem.

Manning’s future also is an open question, although he is far from the biggest problem on this team, and with two years remaining on his contract, the Giants ultimately may keep him. But if the owners make changes involving the coach and/or the GM, then nothing is assured. After all, if the Colts could do away with Peyton Manning, one of the most accomplished quarterbacks in NFL history, the Giants can do the same with his younger brother.

Remember, too, the Giants are almost certain to have a very high draft pick, and there’s a good chance they will take a quarterback with that selection. Even though they made Davis Webb a third-round pick this year, being in position to potentially draft a top five player could prompt them to go with a blue-chip prospect.

The last time the Giants had such a significant changing of the guard was after the 1978 season. They fired coach John McVay and GM Andy Robustelli and soon moved on from quarterback Joe Pisarcik. That led to the hiring of GM George Young, the drafting of Phil Simms and the eventual hiring of Bill Parcells, a trio who gave the franchise its first Super Bowl championship

It was then-commissioner Pete Rozelle who brokered the deal with feuding co-owners Wellington Mara and his nephew, Tim, to hire Young, and that led to an unprecedented run of front-office stability that continues to this day. After Young retired in 1997, he was replaced by hand-picked successor Ernie Accorsi. And when Accorsi retired in 2006, the Giants elevated Reese, a personnel executive who was Young’s last front-office hire in 1997.

Now the sons of the late co-owners Wellington Mara and Bob Tisch may be ready to opt for the kind of franchise-changing moves that haven’t been seen since the Giants bottomed out 39 years ago.

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