Nick Sirianni has to fix the Eagles. For his sake, he has to make sure Jalen Hurts is the solution.

From last season to this one, Jalen Hurts has declined in virtually every tangible, statistical area in which a quarterback can decline.

His completion percentage, touchdown percentage, yards per attempt, yards per game, passer rating, total quarterback rating, rushing attempts, and yards per rushing attempt have all dropped. His interception total and interception percentage have more than doubled. His team will finish, at best, two games worse this season than it did last season.

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Does this mean Hurts has had a poor season? It does not mean that.

There are roughly 25 NFL teams, at a minimum, that would be happy to have their quarterbacks deliver the caliber of play that Hurts has through the Eagles’ first 16 games. But it does mean that Hurts’ play, broadly speaking, hasn’t trended in the right direction. Not in the manner he would have hoped. Not in the manner the Eagles as a whole would have hoped. And certainly not in the manner that Jeffrey Lurie would have hoped when he agreed last offseason to extend Hurts’ contract for five years and what might be as much as $255 million.

But one person’s hopes here might matter most of all: Nick Sirianni’s.

An NFL head coach, any NFL head coach, pretty much takes it for granted anymore that his future is tied to the performance of his starting quarterback. Find a good one, and you buy yourself time. Find a great one, and your job could be secure for a decade or more. Lose one, and you’re at risk. Fail to find another one, and soon enough you’ll become a regular discussion topic on talk shows and podcasts from coast to coast. Even the man who has come to be regarded as the greatest football coach ever, Bill Belichick, has learned this hard lesson in the four years since the man who has come to be regarded as the greatest quarterback ever, Tom Brady, left the Patriots.

Which brings us to Sirianni, Hurts, and Lurie. There has been a lot of conjecture and discussion lately about Sirianni’s future here in the wake of the Eagles’ month-long metamorphosis from the top team in the NFC to an 11-5 question mark. Would Lurie fire him? What would have to happen for Lurie to fire him? A loss in the wild-card round? A bad loss to Dallas or San Francisco in the divisional round? Really? He would fire him?

So many of those answers depend on how the Eagles fare Sunday against the New York Giants and in the postseason. So much of the story remains unwritten. But while all that speculation takes Lurie’s quarter-century-plus as the Eagles’ owner into consideration — he stuck with Andy Reid until he couldn’t anymore; he ditched Chip Kelly quickly; Doug Pederson was gone three years after Super Bowl LII — it omits a vital component: the team’s quarterback situation at any particular time.

Put simply, the better and more stable that situation is or is perceived to be, the less willing Lurie has been to change his head coach.

I’ve made this point and laid out this timeline before, but it’s worth repeating: Reid and Donovan McNabb had 11 years together; Reid lasted three years without him. Kelly felt he was settling for Nick Foles, took a big swing with Sam Bradford, missed, and didn’t finish the 2015 season. Pederson wanted more power and control in his post-Philly Special tenure, and Lurie and Howie Roseman weren’t about to give it to him. But his fate was sealed once he benched Carson Wentz — after Wentz’s rapid disintegration into arguably the league’s worst starting QB — for Hurts.

That thread — the importance that Lurie places on the connection between coach and QB and his actions if he believes it has been severed — stretches to Sirianni. He has to know that. Yes, his mission is to win games. But his mission is also to maximize the Eagles’ investment in Hurts.

“We are there to serve the players,” Sirianni said Friday. “I truly believe that if a player’s not playing to the best of his ability, that’s on me. Now, that doesn’t mean that we don’t correct the mistakes that they made and hold them accountable and say blindly, ‘That’s on me.’ You go in and correct the stuff. But if the detail’s off, it’s a combination. The execution and the detail [weren’t] there, but did I coach it as well as I needed to?’ ... We serve the players.”

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Lurie views a head coach’s role in exactly the same way. So here’s Sirianni, a year removed from helping Hurts reach a level that few, if anyone, had believed he could reach: an MVP candidate, the best player in Super Bowl LVII, a genuine franchise centerpiece. And when the Eagles were 10-1, when they were celebrating in the Lincoln Financial Field end zone on Nov. 26 after Hurts dashed there in overtime to beat the Buffalo Bills, he was at least close to being that player. Now?

“Before we got into the skid we’re in, he’s the No. 1 player people would talk through as far as MVP,” Sirianni said. “Now we’re on a skid. We’ve lost four of our last five, and that goes away.”

He has two weeks to get it back. Or else things might get really interesting.