The Niners are done. Take their word for it.

SANTA CLARA — They’re battered, bruised, injured, and tired.

They’re a team that had big hopes coming into the season but have only big disappointments to show for it.

And at 5-5 on the season Following a 20-17 loss to the Seahawks Sundaythe Niners are still, technically, alive in the NFC, a conference where mediocrity reigns.

But I don’t hear a pulse.

Do you?

There’s no way you could after another lifeless game and another fourth-quarter collapse to a division opponent in which all three phases of the game—offense, defense, and special teams—contributed significantly to the squad’s demise.

The 49ers that took the field on Sunday were not a one-off edition. This is the team we’ve seen since July when they began a dull, boring training camp. They’ve posted a few decent moments against awful teams this regular season, beating the Jets in the season opener and playing one great quarter against the horrendous Cowboys before their bye week. But the steady form of this team has been underwhelming. They play as if they believe they’re entitled to better, and that championship form will magically arrive and stick around until February.

Of course, that’s not how professional football works.

“We have to be better. We have to execute better,” Trent Williams said Sunday. “Sloppy…. We shot ourselves in the foot.”

You could say that after just about every 49ers game this season.

And while we’re repeating ourselves, I’ll again tell you that this team can’t seem to get out of its own way.

Call it a Super Bowl hangover if you must, but playing 20 games — 17 regular-season contests and three playoff games — every season for the last three campaigns has taken its toll. This is what’s left.

Yes, these Niners have reached their expiration date. And to think that this front office spent so much time and money to keep it together.

The evidence is littered on the sideline, with players wearing Niners-branded sweatshirts. It’s on the field, with unknown players playing key roles and key players who don’t look like the guys we saw last season.

Tight end George Kittle — arguably the most important man in the Niners’ offense — was sidelined for Sunday’s game with a hamstring injury. Williams had a bad ankle and, given the Niners’ offensive line depth, had no choice but to play. Nick Bosa played through a hip injury to play Sunday, only to be knocked out of the game by an oblique injury.

“I guess I was compensating,” Bosa said.

And now the Niners will likely have to find a way to compensate without him for at least the next few weeks.

Meanwhile, Christian McCaffrey and Deebo Samuel are, ostensibly, not injured, but they’re playing like shells of their former selves.

Against one of the worst run defenses in the NFL, McCaffrey averaged 4.2 yards per carry Sunday. That’s solid, but when McCaffrey fails to hit hole after hole, such praise rings hollow.

Samuel, meanwhile, is out of juice. Using the wide receiver like a battering ram would always lead to the demise of the “wide back,” and it’s here now. He’s no longer a one-of-a-kind weapon — he’s a detriment to moving the ball on offense.

It’s a tough watch.

But at the same time, the idea of ​​having a veteran team is that, even if they collectively lose a step or two, they’re so experienced that they can handle the little things that win football games.

The Niners don’t even do that. They’re a bad situational football team, flailing in the red zone and on third downs on offense and consistently failing to make big stops on critical defensive series.

And then there are special teams, which are inarguably the worst in the NFL.

Sunday’s contributions to the wooden spoon race: a booted kick return (which luckily went out of bounds) and a never-in-doubt touchback on a punt to set up the Seahawks’ game-winning touchdown drive. Seattle didn’t have anyone back to return the punt, and punter Pat O’Donnell — in his first game with the Niners — didn’t come close to pinning the ball deep in Seattle territory.

The fact that such an error feels inconsequential amid all the special teams follies the Niners have committed this season speaks volumes.

Oh, and head coach Kyle Shanahan went 0-2 on challenges Sunday, and it seemed as if he used up all his offensive creativity on finding ways to keep his backup tight ends off the field in two tight-end sets, opting for an additional tackle instead.

This is the worst kind of football team: a conceited but objectively mediocre squad.