Redskins quarterback Alex Smith is brought down by two Texans defenders, breaking his leg on the play. (John McDonnell/The Washington Post)

Late on Sunday afternoon, Washington Redskins Coach Jay Gruden emerged from the back of the team’s locker room and began walking down a FedEx Field corridor. Outside, the scoreboard said his team had lost, 23-21, to the Houston Texans. Inside the room behind him, doctors had told him his quarterback, Alex Smith, had fractured the tibia and fibula in his lower right leg and would be headed to immediate surgery.

As Gruden walked, his eyes stared at nothing in front of him. He let out a deep breath. Smith had gone down midway through the third quarter on a sack from Houston’s Kareem Jackson, his leg breaking in such a grotesque manner that it provided an eerie reminder of another Redskins quarterback, Joe Theismann, 33 years to the day since his own gruesome leg injury. Anyone who watched Gruden making this postgame walk had to wonder whether the season was crumbling before him.

“To Dallas,” he said when asked where his mind turns now.

Sunday’s loss to Houston left Washington 6-4, and its starting quarterback is lost for the season. The combination makes Thursday’s Thanksgiving game against the Dallas Cowboys perhaps its most important of the season as the Redskins cling precariously to a one-game lead in the NFC East over the Cowboys, the team’s biggest rival.

“It just breaks your heart,” he said of Smith, the quarterback the team wanted most this offseason when it let Kirk Cousins leave in free agency and to whom the franchise gave $94 million to lead its offense through 2022. “Physically, he’ll be fine. Mentally, he’ll be fine. It’s just hard to watch that happen to any athlete on the football team.”

Inside Washington’s locker room, there was sadness. Players looked around with somber faces. There was none of the shouting that sometimes even follows a loss. Everyone knew how badly Smith was hurt and how devastating the loss of a quarterback is to a team.

“It hurts to watch it,” center Chase Roullier said.

But football is a game that does not mourn injured players long. And lost in the despair of watching Smith disappear into the tunnel on the back of a cart was the fact that the Redskins nearly came back and won this game. At the time Smith went down, they were trailing 17-7 to one of the NFL’s best defensive teams. Smith already had been intercepted twice , and the first of those interceptions had been returned 101 yards for a touchdown by the Texans’ Justin Reid. Smith, himself, had a quarterback rating of 29.1 for the day and was having one of his worst games in what has been a slow start with a new team.

“Whenever someone goes down, the next man has to come up, step up for him,” said tight end Vernon Davis, the player who knows Smith the best from years they played together in San Francisco.

And backup Colt McCoy ran onto the field after the Redskins got the ball back with an interception at the Houston 27. Once a star at the University of Texas and considered a possible quarterback of the future for the Cleveland Browns, the 32-year-old McCoy has been the Redskins’ emergency option at quarterback since he played five games in the team’s lost season of 2014.

“You pray for opportunities to get to play,” McCoy said. “You never like to see how it happened today, but for me I just have to go out there and give it all I got.”

“Let’s go get this win” is all Gruden told him.

McCoy ran for four yards on his first play Sunday. Then he lofted a pass that landed in the arms of tight end Jordan Reed, who streaked across the back of the end zone for a nine-yard score, cutting Houston’s lead to 17-14. After a Texans field goal, McCoy then led a drive of 67 yards over the course of 4:22, hitting Reed and wide receivers Josh Doctson and Trey Quinn with quick passes and running 15 yards himself, setting up a seven-yard touchdown run by Adrian Peterson that put the Redskins up 21-20.

It was Peterson’s second touchdown run of the day, and in addition to putting the Redskins ahead, it marked the first time all season the lead had changed in a Washington game.

A crowd that filled two-thirds of FedEx Field roared with hope. Arms waved. Fans sang. It was probably as loud as the stadium has been all season.

And then the great comeback ended.

The Texans moved 47 yards on eight plays, allowing kicker Ka’imi Fairbairn to hit a 54-yard field goal that put Houston ahead for good.

Washington’s final two drives could not bring magic Sunday. Taking over with 52 seconds left on the Washington 35, McCoy (who had 54 yards passing and 35 rushing) moved the Redskins to the Houston 45. Out of timeouts with eight seconds left in the game, Gruden mulled his options: a throw to the end zone or a 63-yard field goal attempt. After conferring with special teams coach Ben Kotwica, he turned over his shoulder to kicker Dustin Hopkins.

“Do we have a shot?” Gruden asked Hopkins.

“Yeah, I’ve got a shot,” Hopkins replied.

Hopkins thought he had hit his kick well. The ball climbed high and straight toward the goal posts, but he noticed the ball was flying too high. It wasn’t moving far enough. He turned his head before the game-winning attempt fell short. Much like Smith’s injury, which many Redskins said they will avoid replays of, it wasn’t worth watching.

“We don’t have to change anything,” Gruden said about the team’s offense going forward. “I think [McCoy] and Alex have very similar skill set, so [the] offense won’t change. That’s the good thing. [We] will continue to do what we’ve been doing and build off the things we’ve done well.”