PHILADELPHIA — It’s December, and the Washington Redskins again look like a team that should petition the NFL to shorten the season. They can’t make it 16 games with a healthy roster, let alone a team playing its best football. For the past three seasons, they have been pondering how to finish. The game — with injuries, with prime time pressure, with situations that require consistency and steady leadership — keeps getting in the way.

In June 2017, back when team President Bruce Allen still pretended to be accountable, he emphasized the need for Washington to win at this critical time of year. The team was coming off an 8-7-1 season in which it lost two late-season home games to Carolina and the New York Giants that could have clinched a playoff berth. You could still feel the sting of that Giants finale on that June day, even as Allen was introducing Doug Williams as the franchise’s new top personnel executive.

“We should not have lost the last game of the season,” Allen said. “And from that Giant game on, the direction of the organization was, ‘We have to get better. We have to find out ways to win that game when we have that opportunity.’ ”

They’re still searching for ways to be their best when it matters most. With four games remaining, Washington has fallen to 6-6 after three straight losses and four defeats in its past five games.

For the second straight season, injuries have been a major hindrance, especially the ones to the offense. With quarterbacks Alex Smith and Colt McCoy now lost for the season to broken legs, you have to consider extreme misfortune the biggest reason Washington is fading and will soon disappear entirely from the postseason picture. Few teams could hold a season together with a No. 3 quarterback and a decimated offensive line. Even fewer could hold it together if that third QB — Mark Sanchez, in this case — came in off the street two weeks ago.

But Coach Jay Gruden’s team cannot simply cry curse. The defense, which is mostly healthy, is amid a severe five-game regression in which it has allowed 430.4 yards per game. The special teams have been solid, not spectacular. As an offensive play-caller, Gruden hasn’t been as patient and creative in the run game as he can be. For as bad as Washington has it right now, the team is compounding its problems.

“We have to play great football around [the quarterback],” Gruden said. “We have to play great defense. We have to play great special teams. And then our running game and our offense has to step up around him to make it easier for him.”

Nothing is easy for Sanchez right now. He made some impactful plays when he first came off the bench, including five straight completions during a two-minute drill that resulted in a second-quarter field goal. But overall, Sanchez completed 13 of 21 passes for 100 puny yards, and he threw an interception. The Washington offense managed 36 yards after halftime. For the game, it had four three-and-out punts in 10 offensive possessions.

You couldn’t blame Washington for losing focus or not coming ready to play. The players competed. They trailed just 14-13 at halftime. They came up with two huge red-zone stops — a Josh Norman interception and a fourth-and-goal stuff — to keep the game within reach. But they made too many mistakes on defense, several of which came because players were too aggressive in hunting turnovers. And when the offense can do nothing but call a few plays and prepare to punt, there’s no opportunity to probe the opponent and get into a rhythm.

“It’s tough,” Norman said. “Guys put their heart into it. We really want to win. … These are the breaks, man.”

This is December, man. Welcome to the time of year that exemplifies why this franchise has been stuck in mediocrity for three seasons.

As the head coach, Gruden now has a 9-10 record after Dec. 1. If you expand and look at his record after Nov. 1 — essentially the second half of every season — it is even worse: 16-23. Under Gruden, Washington tends to be erratic in September, excellent in October, troubling in November and out of gas in December. If it isn’t a McCoy broken leg, it is a poor road performance against the Los Angeles Chargers or the Arizona Cardinals. Or it’s a bad home loss to a team already out of the playoff picture.

The one time December wasn’t an issue for Gruden? It was 2015, and Kirk Cousins was on the ascent. He threw 13 touchdown passes and just one interception in five December (and January) games three years ago. Washington went 4-1 and stormed into the playoffs. Since then, it has been a struggle to keep bodies healthy and to get the team to play to its abilities.

The problem is that, every year, Washington balances its hopes on the unsustainable. This season, that is the defense. Do you understand now why so many were skeptical when the Redskins were winning ugly during their 6-3 start? It was based on the belief that this defense, while much improved on paper, wasn’t established enough to carry the team for the entire season. That is proving true.

After being among the league’s top 10 defenses during the first half of the season, Washington is hemorrhaging yards. The run defense, once the team’s greatest strength, has allowed 134.4 rushing yards per game the past five weeks. For the season, the defense is now allowing 367.4 yards per game and 5.8 yards per play. Even though this defense is better, those numbers are much worse than last season’s. Last year, Washington gave up 347.9 yards per game and 5.3 yards per play.

Safety D.J. Swearinger Sr. is calling for the entire organization to unite and resist a woe-is-me mentality.

“It’s going to take the players and the coaches,” he said. “It’s not just the players. It’s going to take a full group effort for everybody to get this bad taste out of our mouth and get on the right track. A full team effort. It’s on everybody in this organization. We’ve got to do this thing together. If that’s not the mind-set, we might as well hang it up. We can’t point fingers. Man, we’re in this thing together. Everybody got to look at themselves in the mirror and come ready to work.”

In his frustration in Monday night’s 28-13 loss to the Philadelphia Eagles, Chris Thompson almost cried. The running back is normally one of the most upbeat Redskins, but not on Monday night. He sighed. He spoke softly. He talked of his performance with brutal honesty.

“Terrible,” he said after gaining just 25 total yards.

For five weeks, Thompson had worked to return to the field after fracturing a rib in Week 8 against the New York Giants. He just wanted to help, to break the injury cycle, to give his fading team a boost. He had watched calamity do its worst, erasing a 5-2 start and putting Washington in survival mode. He hoped his return could change the story. Instead, he merely had a closer view of McCoy’s injury and what could be season-ending devastation. Thompson envisioned it being a night of healing. But pain persists.

“I mean, honestly I don’t know what to say,” he said. “It’s just … it’s unfortunate. I don’t know what it is. It’s just … (laughs) … I honestly just don’t know what to say, like, to lose two quarterbacks in one year, I’ve never seen anything like it. It’s just tough. I feel like all the guys, we all do the right thing throughout the week. It’s just when game day comes around, we’ve been having a lot of freak stuff happen. It’s something we can’t explain. You can’t figure it out. It’s just unexplainable.”

Thompson and his teammates don’t need to explain the misfortune. They need to overcome it. Otherwise, December will get the best of them, again.

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