Mike Zimmer’s most embarrassing loss as a head coach could be blamed on injuries, or a reliance on a 31-year-old running back with a knee injury, or any of a dozen bumbling offensive plays.

But to blame the offense for a heartless 34-6 loss at home to the Indianapolis Colts on Sunday would be to ignore how the Minnesota Vikings were built, and who they are supposed to be.

Zimmer was hired because of his defensive acumen and leadership. His first mandate was rebuilding a tattered defense, and he did while earning a reputation as an inspirational figure.

On Sunday, Zimmer coached his team in a game with playoff implications, in front of a sellout crowd at home, while wearing a patch over a surgically repaired eye, and his defenders played like his name was Les Steckel.

The Vikings offense shouldn’t have tried to force-feed the ball to Adrian Peterson, but the offense in its current state is supposed to be this team’s least important phase.

The defense is supposed to lead this team, and it never showed up.

Colts running back Frank Gore is 33. He had reached 100 rushing yards just once since the end of the 2014 season before Sunday, when he rushed 26 times for 101 yards. As a team, the Colts rushed 40 times for 161 yards and two touchdowns, including one by Robert Turbin during which he broke or avoided four tackles before spinning into the end zone.

Behind an offensive line that had been as battered and ineffective as the Vikings’, Andrew Luck was not sacked once. He had time to complete passes to eight different receivers.

The Vikings allowed 411 yards and 27 first downs and didn’t force a turnover.

Zimmer should take this personally. His players embarrassed him on Sunday.

The last time the Vikings looked this pathetic in a home loss was when the Packers beat them 31-3 at the Metrodome on Nov. 21, 2010, when the Vikings allowed 31 straight points and succeeded in getting Brad Childress fired.

It was remindful of a December game against a bad Packers team in 1991, when Vikings players lost 27-7 at the Metrodome while making it clear they no longer wanted to play for Jerry Burns.

That’s what is strange and unsettling about Sunday’s loss. There are no signs that the players have anything but affection and admiration for Zimmer — other than the final score.

“I felt like we just came out lackadaisical, like we were just going to get this win,” cornerback Captain Munnerlyn said. “Like they were going to read our name or look at the stats and lay down for us, that we have a good football team and a good defense, and just lay down.

“It doesn’t work like that.”

Munnerlyn said he was embarrassed. Zimmer hinted he felt the same.

“Very poor, lethargic, didn’t get off blocks, didn’t make tackles, busted coverage, didn’t cover people, poor on third down,” Zimmer said.

While the offense has been devastated by injuries, the defense had only one excuse on Sunday: the absence of Harrison Smith.

Luck was smart and gifted enough to attack the void left by Smith, throwing to the middle of the field frequently. That, along with the Colts’ power running, turned the Vikings’ usually aggressive defense into crash test dummies.

The Vikings have lost seven of their past nine games. Many of those losses have been understandable, given their injuries, and most of them have been close.

Sunday, the Vikings allowed a mediocre finesse team to physically whip them. For a football team, that leaves the worst kind of psychic scar.

On Christmas Eve, the Vikings will play a streaking Packers team at Lambeau, in a game that will mean much to Green Bay.

Two days ago, that game promised to decide the fate of the Vikings’ season. Now you have to wonder if they’ll even have the pride to put up a fight.

Jim Souhan’s podcast can be heard at MalePatternPodcasts.com. On Twitter: @SouhanStrib. jsouhan@startribune.com