Twice in the past, the Washington Redskins had been dominated by an opponent’s pass rush so thoroughly that they gave up nine sacks. The first time came in 1964. The next came in 1978.

And along came Sunday. The Buffalo Bills had racked up all of four sacks in six games so far this season. By halftime at Rogers Centre, they had matched that total. By the end of a 23-0 demolition of the Redskins, they had nine — more than twice than they had all year, more than the Redskins had allowed in 33 years, more than any team in any game of the 2011 NFL season.

How does that happen?

“That’s a good question,” Coach Mike Shanahan said.

It was, in the moments after the game, unanswerable. The Redskins have a patchwork offensive line. They fell behind 20-0 early in the third quarter, so they had to pass. But the Bills ranked last — 32nd out of 32 NFL teams — in getting to the quarterback.

And they got nine sacks. The question — how does that happen? — was inescapable in a disconsolate locker room.

“This is a tricky one to try to give answers for right now, because I kind of don’t have any answers right now,” said John Beck, the quarterback who spent as much time staring at the Rogers Centre roof as he did trying to find receivers downfield. “I’m trying to figure that out myself.”

The figuring out will begin in earnest Monday, when coaches and players will endure the misery of watching the tape. What they’ll see is gruesome: eight different Bills in on those nine sacks, led by defensive end Marcell Dareus, who had 21 / 2. They will see four sacks in the second quarter, when the game was still a game, before the Redskins were forced to pass over and over. Those included untouched safety Jairus Byrd coming on a third-down blitz, one that turned the Redskins’ best scoring opportunity into a 49-yard field goal attempt from Graham Gano. The kick was blocked. The shutout continued.

And they’ll see, by the Redskins’ first possession of the second half, an offense that had to throw the ball, a defense that knew it, and the bloodshed that resulted.

“Any time you’re down 20, and you’re passing it, that’s not an ideal situation, because they just tee off,” left guard Will Montgomery said. “When the score’s even or we’re ahead, that’s not going to happen.”

Montgomery has been the left guard for all of two weeks, and the Redskins’ physical state on the offensive line surely contributed to Sunday’s debacle. Center Erik Cook, a seventh-round draft choice in 2010, played his third NFL game, shifting Montgomery to guard, where starter Kory Lichtensteiger is out with a torn anterior cruciate ligament. Left tackle Trent Williams watched Sunday from the sideline, and he’ll likely miss two more weeks with a high ankle sprain.

The result: Beck dropped back to pass 42 times. He was sacked nearly once every four of those times.

“It sucks,” said veteran Sean Locklear, filling in for Williams at left tackle. “Straight pass rush. They’re not worried about anything but getting to the quarterback. It’s a bind. Nobody wants to be in that situation.”

The Redskins appeared in that situation from the very first snap Sunday against a Buffalo team that hadn’t consistently pressured anyone, all year. Now, with their health still in question and their confidence eroded, “we’ve got to have some kind of way to get out of that,” tight end Fred Davis said.

“Beck was getting hit right away,” Davis said. “It’s hard for a quarterback to get in a rhythm like that.”

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