Redskins quarterback Kirk Cousins had largely avoided big mistakes this season, but he threw a critical interception in Sunday’s loss to Minnesota. (Toni L. Sandys/The Washington Post)
Columnist

A really bad thing happened to the Washington Redskins over the past week: Their health improved. For most teams, that qualifies as good news. For the mercurial herd representing the nation’s capital, it was complicated, as usual.

The players were coming off the high of a rare victory in Seattle. They had earned immense credit for their resolve. Now, reinforcements were arriving at the right time. On Sunday, the entire starting offensive line was able to play, as were wide receiver Jamison Crowder and safety Deshazor Everett. After weeks of clinging to hope and staving off doomsday early-season scenarios, they managed to claw within one quality performance at home against the NFC North-leading Minnesota Vikings from returning to the playoff picture.

Naturally, they blew it.

Naturally, this perplexing group became stronger — and got weaker.

In a 38-30 loss at FedEx Field on Sunday, Washington played its most disappointing game of the season. Forget that the team technically stayed in the game until the end. That’s just because every NFL matchup is pre-programmed to be close. The defense strayed from the improvement it has shown and started gift-wrapping yards again. Kirk Cousins — yes, the quarterback I told you was avoiding devastating interceptions this season in my last column — threw a horrible pick late in the second quarter that helped the Vikings take over the game. The offense was a mess in critical situations: 5 for 14 on third down and just 2 for 4 in the red zone. Even cornerback Josh Norman, who is among the team’s most consistent players, turned in an effort that he dubbed “probably my worst game since my rookie season.”

As much as you try to analyze Washington on a sophisticated level, this is really quite simple. It is just an average team. Start thinking these players as lousy, and they’ll go to Seattle and shock you. Start thinking they’re good, and they’ll turn soft against a superior team. Start considering them uninspiring, and they’ll inspire. Start defining them as resilient, and they’ll act lackadaisical.

It is as if an invisible fence controls the Redskins, ensuring they remain in the middle of the NFL pack. In the past three seasons, they haven’t met a situation, good or bad, that they couldn’t turn into a .500-ish record.

It’s their identity. Until they prove otherwise, it’s unquestionably who they are.

“We’ve got to get up out of this .500/under .500 level,” Norman said, shaking his head. “We have the capabilities to do it, man. We’ve just got to do it.”

It’s impossible to do without momentum, without good performances leading to more good play, without any rhythm or repetition from game to game. Washington (4-5) is among the NFL’s most confounding week-to-week mysteries, which is great when the team is given no chance but absolutely awful when it is needed to act, well, stable.

After a half-season of impressive improvement on defense, Washington entered Sunday needing to be prepared to play another physical, low-scoring affair against the Vikings, who may have the league’s most complete defense. Instead, it was a shootout. It was the highest-scoring game that Washington has participated in since 2014. That’s cool, as long as a few spurts of defensive competence are exhibited. But aside from two D.J. Swearinger interceptions and a few encouraging plays when the game got close in the fourth quarter, Washington performed as if former defensive coordinators Joe Barry and Jim Haslett had locked Greg Manusky in a closet and conspired to ruin their former team.

Everything was off. In the first half, Minnesota had possession of the ball for only 11:28 yet still gained 247 yards and scored 28 points.

The Vikings ran the ball well early. Quarterback Case Keenum threw for 304 yards and four touchdowns. Adam Thielen amassed 166 receiving yards, and Stefon Diggs made Norman look silly on a double move.

The Vikings scored touchdowns on five of their first six possessions. They scored 21 points in a span of 4:27. On offense, Washington produced 30 points and 394 yards against the Vikings. Although the Redskins lamented several missed opportunities, the production amounts to an incredible day against Minnesota’s fearsome unit. Still, the Washington defense needed more help.

“It feels like we got blown out defensively because we gave up 38 points,” linebacker Ryan Kerrigan said. “Our offense scored 30 points, and that should be enough.”

Coach Jay Gruden called it “one of the worst defensive performances we’ve had since I’ve been here, in the first half.” And he has seen some bad ones here. Boy, he has seen some bad ones.

This defense is supposed to be better. This defense has been better. It’s the same unit that, just a week ago, Gruden challenged to carry the team while his battered offense healed. It responded by keeping Seattle out of the end zone until the fourth quarter and spurring a 17-14 victory.

The Vikings (7-2) are better than the Seahawks overall, and their offense is definitely less erratic. Still, they’re not so good that they should be scoring at will, especially on the road. But Washington struggles with consistency. You keep thinking that it’s something the team will grow out of, through maturity and roster stability. But what if it’s a permanent trait, a fatal flaw?

For certain, the players and coaches didn’t see a regression coming.

“It’s tough to say because I felt like we had a great week of practice,” Kerrigan said. “We really did. Guys were dialed in, locked in, and energy was good. Even today, I thought the energy was good. We just . . . they were just making plays. It’s really tough to pinpoint because, I feel like, we’ve had some good weeks of practice, we’ve had some good games, and then we have games like today where it’s a real head-scratcher.”

Norman gnashed his teeth. This could have been the game in which Washington finally got right. It wasn’t just about the outcome. The Redskins were healthy enough to play a complete game and, at least, challenge a very good team. This was a huge chance to get back into the season, to start to make a playoff push, to be more than average. But the depleted version of this team played with more toughness than this replenished squad. Even after factoring in that some players would be rusty in their return, this was pitiful, mostly because the defense that had held the squad together relaxed at the worst time.

“We were so lackadaisical,” Norman said. “We didn’t have crap today. We really didn’t. It was like, ‘Wow, what is going on?’ ”

Sadly, there is an answer to Norman’s question. What is going on? The usual. Injured or healthy, Washington can’t sustain anything.

It’s not merely a frustration. It’s a habit — a troubling, crippling habit.

For more by Jerry Brewer, visit washingtonpost.com/brewer.