Nick Sirianni accepted blame, but the entire Eagles offensive staff — including Kevin Patullo and Jeff Stoutland — failed to prepare for a defensive wrinkle that Jay Glazer openly reported hours before the game.

Nick Sirianni took the blame for Sunday’s 21-point collapse in Arlington, Texas. He’s the head coach — he’s “gotta do a better job” — but the failure runs far deeper than just him. The entire offensive brain trust deserves heat: offensive coordinator Kevin Patullo, offensive line coach Jeff Stoutland, and Sirianni himself all missed something that should never have been missed.

Poor play-calling was only part of the problem. The bigger, more alarming issue was the Eagles’ complete lack of preparation and adjustment to Dallas’ new-look defensive front. After the game, Landon Dickerson laid out exactly what the Cowboys did — and how unprepared the Eagles were for it.

Asked what defensive look Dallas showed, Dickerson said:

“Just five-down fronts. It’s not usually, typically something they were running a whole lot, and turns out that was their flavor of the day.”

Asked how the offensive line can counter unexpected looks, he added:

“I think a big thing is … time on task.”

That quote says everything. The Cowboys changed their front. The Eagles didn’t adjust. Worse, they didn’t even anticipate it.

And here’s the part that makes this unacceptable: while the Eagles were apparently blindsided, NFL insider Jay Glazer wasn’t. On the Fox pregame show — before the game even started — Glazer reported that Dallas planned to use this exact new front, the same alignment they debuted in Las Vegas just over a week ago.

If a national reporter knows a schematic change is coming, how do Sirianni, Patullo, and Stoutland miss it with an entire week of film, game-planning, and scouting? How does a TV insider have more information than an NFL coaching staff paid millions to prepare for divisional opponents?

That’s not a bad day.

That’s a breakdown in process.

And it’s flat-out unacceptable.