If Jets fans didn’t fully appreciate their 27-year-old dancing bear of a center before this year, they do now. It’s one thing to regurgitate the conventional wisdom about how good he is. It’s another thing to watch an offense crumble in his absence, as the Jets’ did during the two games Mangold missed earlier this year. It might be hard for the layman to assess an offensive lineman’s contribution on the field, but it was easy enough to see what happened to the Jets when Mangold was off of it.

Yesterday’s game against the Eagles figured to be the culmination of a season-long ramp-up. The Jets’ running game, the subject of a season-long existential crisis about the team’s “identity,” was finally rounding into form. A week after amassing 159 rushing yards against Kansas City—43 more than the league average—the Jets were going up against a poor run defense in Philadelphia.

Philadelphia’s trademark “wide-nine” alignment of its ends facilitates one of the game’s best pass rushes. But it leaves the Eagles vulnerable to runs up the middle, which, in the Jets’ case, are powered by Mangold.

This was the Jets’ strategy early on. On their second play from scrimmage, running back Shonn Greene followed a Mangold block up the middle for a 12-yard burst. The man Mangold blocked, Cullen Jenkins, had lined up over left guard Matt Slauson. For the play to be successful, Mangold had to get his body into Jenkins before Jenkins could get into the backfield to disrupt Greene’s path. Mangold, a natural athlete whose best attribute is his quickness off the snap and the precision of his blocking angles, easily executed his assignment, getting optimal positioning before driving an off-balance Jenkins away from the action.

The next play was more of the same. Mangold quickly got a body on his man to afford Greene, who had taken a direct snap on this fast-developing play, room to accumulate steam for a 6-yard gain. The next play—the Jets’ fourth from scrimmage—was a carbon copy of the 12-yard gain two plays before. Mangold, using his uncommon spryness, walled off Jenkins before he could get into the backfield, and Greene dashed up the middle for 13 yards. Three straight running plays up the middle had yielded 31 yards. It was all going according to plan. The Jets couldn’t have gotten off to a better start.

But then, beginning two plays later with Santonio Holmes’s fumble that was returned for an Eagles touchdown, a sequence of catastrophic events unfolded that swiftly and shockingly placed the Jets in a 28-0 hole.

The adage that football games are determined by the war of attrition in the trenches is well and good, and it applies to many games. But a 28-0 deficit pretty much renders it moot. So much for the “ground and pound” game plan anchored by Mangold. The deficit meant that the Jets would have to do what they do worst—pass the ball—while allowing the Eagles’ dangerous pass rush, which ranked second in the league in sacks coming into yesterday, to do what they do best.

The results were predictable. Quarterback Mark Sanchez was sacked four times, sustaining a neck injury on one of them that the Jets can only hope is not serious. The Eagles’ pass rush negated the gains the Jets’ offensive line had made in pass-blocking during the previous three games, during which they allowed just two sacks and a handful of pressures.

And Mangold was not immune. In the second quarter, the Eagles ran a stunt, in which defensive end Philip Hunt looped around from the edge and charged up the middle. Mangold, who had seen defenders clear out in front of him and was left standing in space by himself, was taken by surprise by Hunt’s charge. Hunt plowed into him and deposited him on the ground before sacking Sanchez.

Taken by surprise and knocked on his ass. It was a microcosm for the Jets’ day.