Redskins wide receiver Jabar Gaffney hauls in a 16-yard touchdown pass from Rex Grossman late in the first half against Dallas on Nov. 20, the result of a play that was two months in the making. (Jonathan Newton/THE WASHINGTON POST)

On the morning of Friday, Nov. 18, as most of the Washington Redskins gathered for special teams meetings, offensive coordinator Kyle Shanahan called quarterback Rex Grossman into his office. On a flat-screen television, Shanahan ran tape of what seemed to be an innocuous play from nearly two months earlier — a third-down pass on a Monday night in Dallas, when Grossman had looked for wide receiver Terrence Austin. The play was designed to go for a touchdown, but Austin tripped, and the ball fell incomplete.

As Shanahan and Grossman met, the Redskins were two days away from hosting the Cowboys again. They had scored just one touchdown in three games. They needed a play — one play — to get them going. What if the same situation arose, the Cowboys came with a similar defense, and the Redskins tried again, with a slight alteration?

“I was like: ‘I like it. Let’s call it,’ ” Grossman said. “We need to have some explosive plays there that get us touchdowns, instead of just . . .”

The message was implied: Instead of just stalling, settling for field goals, losing.

Less than an hour later, the Redskins gathered on the practice field, where the offense would do what it does every Friday: Install the package of plays to be used in the red zone. During that session, Shanahan told Grossman to call “North Right Clamp, H-2 Special, Z Bingo Choice, X Corner Post.”

In any given NFL game, there are roughly 130 snaps. Coaches and players know that any one of them can change a game and, thereby, a season. By the time the Redskins selected that play as one they might use in the second Dallas game, they desperately needed a moment that could put a quarterback controversy behind them and show they could score.

The play’s evolution — from the first time Shanahan called a variation of it on Sept. 26, to its appearance on his video screen weeks later, to its installation and eventual execution against Dallas the second time around — illustrates how much effort and preparation goes into drawing up, calling and running a potential game-changer for each NFL team in each NFL game, every single week of the season.

It was just one of perhaps 100 plays the Redskins had available specifically for the Cowboys. Each must be watched, reconsidered, broken down and built back up again, perhaps with a change or two, influenced by guesswork about how the opponent will respond.

“That’s the only way you get better,” said Mike Shanahan, the Redskins’ head coach and Kyle’s father. “You take a look at a play and you say: ‘Hey, was it the right call? Was it the right defense? Did we work on it enough? Did we blitz? Were we at the right depth? Did we have the right matchups with the right players?’”

Meticulous play design

When the Redskins played at Dallas in Week 3, they were locked in a 6-6 tie as they drove downfield midway through the second quarter. A three-yard pass from Grossman to rookie running back Roy Helu pushed the ball into the red zone — inside the 20-yard line — but left them in a difficult spot: third and five from the 18.

Kyle Shanahan looked at his play call sheet, where he listed his top choices for third-down plays and others to be run between the 16- and 20-yard lines. He wanted to take a shot at the end zone. The Redskins sent in their “Gator” personnel group — three receivers, one tight end and one running back. Over his headset, Shanahan radioed in a play to Grossman: North Left Clamp, H-2 Special, Z Bingo Choice, X Corner.

Though the play’s name seems confusing, the language is meticulously designed. The first phrase is the formation. In this case, “North Left Clamp” called for the tight end to be on the left side, with the “Z” receiver, the receiver on the tight end’s side, fairly tight to the formation.

Each player’s responsibility is spelled out from there. “H-2 Special” is the protection; in this case, running back Tim Hightower was to stay in and help block ferocious Dallas defensive end DeMarcus Ware. Then come the pass routes: The “Z” receiver runs a “Bingo” route, a 12-yard crossing pattern. The “Gator” or “slot” receiver — who was not named as Grossman spoke, mostly to trim down the number of words the quarterback had to speak in the huddle — runs a “choice” route, sprinting five yards upfield and cutting to the sideline. And the “X” receiver — who is lined up just outside the slot receiver, but at the line of scrimmage — runs a corner route.

When Grossman got to the line of scrimmage, he surveyed the coverage. He saw three defensive backs to his right — where Austin lined up as the “X” receiver, with Santana Moss as the slot man.

“You could tell that the safety and the outside corner were doubling Santana,” Grossman said. That would leave Austin one-on-one with the remaining cornerback. That cornerback, Alan Ball, lined up inside of Austin.

“I knew I had an out-breaking route, and he was playing inside me,” Austin said. “I knew I had the advantage.”

All he had to do was beat his man, and the Redskins would score a touchdown.

“We had it,” Grossman said.

Grossman looked at Austin, and only Austin. He lofted his pass. And just as it appeared that Austin was in the clear, Ball cut under him. “He clipped the back of my feet,” Austin said, and he stumbled. One play, perfectly designed to change a game, became a harmless footnote.

On fourth down, the Redskins lined up for a 36-yard field goal. Dallas blocked it. Washington lost, 18-16.

A slight twist

As they prepared to host the Cowboys in Week 11, the Redskins were on a five-game losing streak. Their offense — which had endured a run of devastating injuries, the benching of Grossman for John Beck, then the benching of Beck for Grossman again — was among the worst in the NFL.

“When you go through a bad stretch like we did,” Shanahan said, “it’s more of a grind and not as much fun.”

It is, though, his job. On Thursday nights, his specific responsibility is to help come up with plays the Redskins will use when they reach the red zone. That led him to the group of plays Washington had used in the first game against Dallas. That led him to the incomplete pass to Austin. They couldn’t run it the exact same way, though. Dallas might be ready for that.

“You want to offset one of your tendencies,” Mike Shanahan said.

So on Thursday night, before Grossman left Redskins Park, Kyle Shanahan asked him what he thought about running that same play, but with a slight twist. Instead of the “X” receiver running a corner route, as Austin had done, what if he faked to the corner, but then turned to the post? Grossman liked it. Shanahan wasn’t as convinced.

“If we didn’t get the right look, I was afraid that we wouldn’t be able to hold up [our pass protection] on the play, and it’d be a sack,” he said. “It was something I don’t want to risk versus that good of a pass-rush team.”

On Fridays, Shanahan meets with the quarterbacks at 7:30 a.m. After that meeting on Nov. 18, he took the play out of the Redskins’ red zone package. Yet it ate at him.

“That was the [defensive] look we wanted it for, but I got to thinking, ‘What happens if we get the other 12 looks?,’” he said. “It’s a long-developing play. And those plays, you always got to decide: If you don’t get the right look, are you putting your players in position to really mess up?”

Given the way the Redskins’ offense was going, though, Shanahan also knew the team needed options on which, if everything broke right, it could score from outside the 10. The Redskins needed looks to the end zone. They needed some sort of spark.

“We need some plays that if they don’t give us the right look,” Grossman said, “at least we tried.”

So as Shanahan watched the play again and again, “I got more excited,” he said. He called Grossman into his office. Then he grabbed receiver Jabar Gaffney as well. Again, he asked them what they thought.

“They very rarely say they’re not into it, especially if it’s a play for a touchdown,” Shanahan said. “I talked with them, through the issues. What if we get a different look?”

The play’s name had to be slightly altered to indicate the new route for Gaffney, who was playing the “X” position in place of Austin. So was born North Right Clamp, H-2 Special, Z Bingo Choice, X Corner Post. Less than an hour later, they ran it at practice. It went for a touchdown. The next day, Grossman told Shanahan: “That’s my favorite red-zone play for this week.”

‘I knew I had to sell it’

Near the end of the first half of their Nov. 20 game against the Cowboys at FedEx Field, the Redskins trailed, 10-7. They hadn’t led a game since Oct. 2, but using the no-huddle offense, they moved the ball to the Dallas 20. On first down, Helu ran for four yards. On second down, with the clock running, Grossman looked for wide receiver Donte Stallworth, but his pass fell incomplete.

It was third and six from the Dallas 16. “I’m sure everybody in the stadium was figuring it’d be 10-10 at halftime,” Grossman said.

The Redskins called the play once, but as they got to the line of scrimmage, the play clock wound down and they had to call a timeout. But Shanahan didn’t waver. The call: North Right Clamp, H-2 Special, Z Bingo Choice, X Corner Post.

“I felt confident calling it,” Shanahan said.

One key to the play, though, was the Cowboys double-teaming the slot receiver, which would leave Gaffney one-on-one with a corner, as Austin had been in the first Dallas game. But Moss was injured, out with a broken hand. In his place was David Anderson, a veteran picked up off waivers from Houston.

The ball was on the right hash mark, so the formation was slightly different than it had been in Dallas — “North Right Clamp” put tight end Fred Davis on the right side. Gaffney and Anderson lined up to Grossman’s left. When Grossman got to the line of scrimmage, he saw a wrinkle in the Cowboys’ coverage. Ball, the Dallas cornerback, was deep on the outside at the 8; another cornerback, Orlando Scandrick, lined up over the slot, clearly taking Anderson by himself; and safety Gerald Sensabaugh waited inside the 5, opposite Gaffney. If Scandrick went with Anderson, Ball and Sensabaugh could be left to double-team Gaffney.

“I thought, ‘Oh no,’ ” Grossman said.

The burden, immediately, fell to Gaffney. In order for the play to work — for Dallas to assume Gaffney would run a corner route, as Austin had done in the first game — Gaffney had to convince Sensabaugh and Ball that he would head to the corner.

“I was scared,” Gaffney said. “I knew I had to sell it.”

During a play, the process of selling a fake occurs in less than a second. During a career, it can develop slowly.

“You have to do it with your shoulders, your head,” said Keenan McCardell, the Redskins’ receivers coach who played wideout for 16 years in the NFL. “I’m a big believer that if you give a defender your head to the corner, he can’t help but think that you’re going that way.”

As Grossman surveyed the defense, he decided he had two options: Throw the ball for a touchdown to Gaffney or throw it away, keeping the Redskins alive for a field goal. In order to throw to Gaffney, Grossman had to see his receiver cut in front of Sensabaugh — or “cross his face,” as players say. It is the equivalent, McCardell said, of staying between the ball and your man in basketball.

“If you don’t do it, the quarterback has no chance,” Gaffney said. “A quarterback that throws on timing like Rex does, most of the time he throws it out there expecting you to cross his face. And if you don’t, something bad could happen.”

That requires a hurry-up-and-wait approach.

“I always say, ‘Patience, patience,’” McCardell said. “What I mean by patience is don’t be slow to it, but be patient enough to get him to bite and quick enough to get back across his face.”

When the ball was snapped, the Cowboys rushed only three men, dropping eight into coverage. Helu, the lone back, went to his right to help tackle Jammal Brown with defensive end Jason Hatcher. Anthony Armstrong, the “Z” receiver lined up on the right side, ran his 12-yard in route, but served only to, as Grossman said, “occupy coverage,” distracting Dallas defenders. Ware, a five-time Pro Bowler, rushed upfield against left tackle Trent Williams, then tried to spin back to get to Grossman. Williams contained him. Grossman took a five-step drop, unhindered.

“I was watching Sensabaugh the whole way,” Grossman said.

Had Gaffney continued to the corner — as Austin had in the first game — Sensabaugh had help to the outside in Ball. Still, Gaffney sold the fake well enough that Sensabaugh couldn’t help himself.

“He bit just enough to have him cross his face,” Grossman said. “The protection was great, which allowed me to not only wait on him for a second, but to really see it. I could step up and really see Sensabaugh, have time, feel comfortable and let it rip.”

That’s what Grossman did. When Gaffney planted his left foot and cut back to the post, Grossman gunned the ball toward the back of the end zone. Sensabaugh draped himself on Gaffney’s back, but the throw was perfect. The Redskins had just their third touchdown pass, and their first lead, in six weeks.

By day’s end, Dallas would pull out a 27-24 win in overtime. But the Washington offense produced more points than it had all season. In a year gone bad, one play helped bring optimism to a downtrodden unit.

“It definitely changed everybody,” Grossman said. “Momentum is a real thing in sports. I don’t quite understand that phenomenon, but it’s a real thing. And that one play definitely allowed our offense to get into a rhythm that we hadn’t had for a while.”

The Redskins may or may not get back into that rhythm Sunday against the New York Jets. Whether they do or not, there will be a play — or two, or five, or 20 — that could alter the entire game. They will be tweaked and tailored, based on the tendencies of the Redskins, the Jets, or both.

“That’s why I like being a football coach,” Shanahan said.