NFL

Tracing the roots of this Giants nightmare to one fateful day

There is no one day we can mark on the calendar to unequivocally signify: This is where it all went bad. No exact instant we can stamp as the beginning of the demise of the Giants’ offense.

If we want to specify a time and place, a precise moment to start the clock on the tick, tick, tick of a team in descent, let us go back to the night of April 30, 2015.

The site: the Auditorium Theater in Chicago. The event: the first round of the draft.

The Giants, with the No. 9-overall selection, took Ereck Flowers, a big, young and raw left tackle from Miami. This was thought to be the finishing touch for a rebuilt offensive line, the final piece after taking Justin Pugh in the first round in 2013 and Weston Richburg in the second round in 2014. Flowers was the biggest and strongest of a trio of fresh-faced linemen projected to protect Eli Manning into his advancing years.

The hot mess that is the Giants offense today cannot be blamed on one player, even if that player was such a dismal failure. None of the three supposed building-block linemen are on the roster. Pugh and Richburg found big money with the Cardinals and 49ers, respectively. Flowers was dumped earlier this season and is riding the Jaguars’ bench.

Manning remains, there is a new and not improved offensive line in front of him as he ages, his physical skills and reaction time show predictable fraying. The Giants are 1-7 and find themselves confronting another offensive crisis.

“Richburg and Pugh are average players and the Flowers pick has still haunted this team,’’ an NFL source who closely monitors the Giants told The Post. “I think the Giants made the right call. Both Richburg and Pugh are decent players. They were not worth the contracts they signed.’’

To those who get frustrated with this constant looking backward, recounting the sins of the previous front office, it must be done to see how the Giants got into this predicament. The failures in scouting these linemen necessitated a heavy dive into free agency, throwing money at the problem, and produced Nate Solder and Patrick Omameh. Solder is the starting left tackle, a good player getting paid like a great one. Omameh was benched after six games.

“If you pick at nine and you purchase a left tackle and it doesn’t work out, the problem doesn’t go away, then you have to overpay in free agency to go get Nate Solder and you’re seeing what you get when you overpay sometimes,’’ Brian Baldinger, a former NFL offensive lineman and currently an NFL Network analyst, told The Post.

The culpability of the offensive line — it is particularly weak in run blocking for rookie phenom Saquon Barkley — is intertwined with Manning’s age and increasing reluctance to stand in and take a heavy hit. There is also new coach Pat Shurmur’s offensive system, which has not impressed NFL insiders contacted by The Post, as far as finding ways to scheme around the deficiencies of the offensive line and best utilize Barkley in the running game while also featuring receiver Odell Beckham Jr.

“I’m a fan of Pat Shurmur, he’s been around football a long time and he’s a good guy,’’ the NFL source said. “I don’t feel he’s helped this offense out, at all.’’

“I just don’t know what the offense is right now, I can’t identify it,’’ Baldinger said. “It seems like they just call plays.’’

The Giants are on their bye week and Shurmur vowed to study what went right and what went wrong and make the necessary adjustments. A starting point: Do everything in his power to get Barkley 20 rushing attempts per game — his high is 18 in the season-opening loss to the Jaguars — and ease some of the pressure off an offensive line that has allowed an NFL-high 31 sacks of Manning.

“Thirty-one sacks through eight games is ridiculous,’’ the NFL source said. “That’s not even NFL football.’’

Barkley is viewed by the Giants as a generational talent, yet his arrival has not taken a load off Manning, who is averaging 39.4 passes per game. That is the fifth-highest total in the league, behind just Joe Flacco (42.8), Kirk Cousins (42.6), Ben Roethlisberger (42.4) and Aaron Rodgers (40.6). That the Giants are usually trailing factors into how often Shurmur asks Manning to throw it, but the deficits have rarely been unmanageable until late in the games. In his 15th season, Manning cannot carry the offense and should not be expected to do so.

“You get Saquon going and then take your shots,’’ Baldinger said. “I just haven’t seen much of that.’’

Here is a question posed by the NFL source: “If someone asks you what is the signature Giants running play, what would you say? That’s a problem. They don’t have a signature running play.’’

It did not help that center Jon Halapio suffered a serious ankle injury in Week 3 and was lost for the remainder of the season. The only linemen to play every game at the same spot are Solder and rookie Will Hernandez at left guard. The lack of continuity, and what must be considered an abject lack of talent, in some cases, has the line misfiring on basic, elementary twists and stunts by defenders. Of the seven sacks allowed against the Redskins, six came on garden-variety four-man defensive pressure.

Baldinger called right tackle Chad Wheeler “a backup player until he develops further.’’ Hernandez as a second-round pick shows great promise but he is learning on the job. He is responsible for six sacks and his strengths are not being fully utilized within a pass-happy offense.

“I think Gettleman got it right with Hernandez, he’s going to be a heck of a player,’’ the NFL source said. “Anybody that drafted him should not be expecting him to pass protect 45 times a game. He’s out there to kick ass, he’s a mauler, grind them and punish them.’’

The Giants, desperate for a left tackle and shell-shocked after years of Flowers, signed Solder to a four-year, $62 million contract, guaranteeing him $34.8 million.

“It wasn’t any secret why [Patriots coach Bill] Belichick was not going to pay the kind of money the Giants paid for him,’’ Baldinger said.

Solder has endured some rough moments but he is a solid player. The adjustment from blocking for Tom Brady to protecting Manning’s blind side has not gone smoothly. Solder against a speed rusher prefers to run the rusher by the quarterback, expecting the quarterback to step up in the pocket. Brady is a master at this. The Giants’ guards are getting beat so often there is nowhere for Manning to step up.

Manning, of course, has a hand in the mess. He is not the same at 37 as he was at 27, or even at 33. Asked if he sees signs Manning’s arm is fading a bit, a national NFL scout told The Post: “Yeah, I do. He was never a rocket arm, he didn’t have that laser. But he had good anticipation and good arm strength.’’

Easing off Manning with more Barkley would help.

“Age and time catches up with the greatest players,’’ the scout said. “Eli had his day in the sun, but the last few years there has been a drop-off. They should have got a quarterback three years ago to back up Eli and develop him for when Eli starts fading. Even though he’s a legend with the two Super Bowl rings, you have to have a guy ready to go behind him and that didn’t happen.’’

It did not happen. Not much has gone right for the Giants when it comes to fixing their still-broken offense.