Usually the only responsible way to write about a preseason game is to type "It doesn't matter," then copy and paste the phrase until you run out of space.

It doesn't matter … it doesn't matter … And yet if you want to feel nervous about the 2017 Vikings — if you, in other words, want to be a Vikings fan — you are allowed two weeks of angst over the brutal first-half performance Sunday night in the third and supposedly most important preseason game.

Before the bottom of the roster pulled out a 32-31 victory on the last play…

• The presumptive starting offensive line couldn't pull off an impersonation of a speed bump.

• The first-team offense went scoreless, leaving it with three points in 12 preseason drives.

• The budding star receiver, Stefon Diggs, dropped two passes in the first half.

Tom Wallace — Star Tribune, Star Tribune
Minnesota Vikings players ran on the field and celebrated at the end of the game Sunday after Minnesota beat San Francisco by a final score of 32-31.

• The Vikings defense looked confused and overmatched by a team that finished 2-14 last season.

The Vikings' first teams lost the first half 14-0. While that might not require panic, it was clear afterward the team itself wasn't happy.

"Sporadic," coach Mike Zimmer said of the offensive line.

"You've got to nip it in the bud," cornerback Xavier Rhodes said. "We didn't play well."

"Not good enough," receiver Adam Thielen said. "It doesn't get you, until it gets you."

The offensive line keeps getting this franchise in trouble. The key players have spent little time together, and right tackle Mike Remmers had trouble pass-blocking Sunday. The line destroyed last season and there is no evidence to date that it will be markedly better.

Diggs dropping passes? The defense looking confused? Those are more easily attributable to the nature of preseason games, when veterans' minds drift, and different coaches adopt different philosophies about game plans.

New 49ers coach Kyle Shanahan is renowned for his game plans and offensive schemes. In a regular-season game, a duel between him and Zimmer would be fascinating.

That would hardly be the word for that matchup Sunday. Shanahan's offense produced all-too-easy touchdown passes on two of its first three drives.

On the first, Marquise Goodwin ran past the secondary for a 46-yard TD. Rhodes let Goodwin get past him, and admitted he got caught looking into the 49ers' backfield.

On the second, a 24-yard catch and run by Carlos Hyde, the entire Vikings defense looked asleep.

This is where admonitions about preseason football come into play.

Shanahan was intent on building confidence for his team in the last preseason game that matters, if any of them matter. Zimmer was intent on saving his game-planning for the regular season.

What's disturbing about the Vikings' offensive problems is that they are identical to last season, when the team lost eight of its last 11 games.

Sunday, Bradford was sacked three times. That number would have risen if he hadn't released the ball quickly under pressure several other times, and if he hadn't spun out of a possible safety in the second quarter.

While this offensive line hasn't earned the benefit of the doubt, Bradford has. He sent an NFL record by completing 71.6 percent of his passes last season, even while under constant duress. Sunday, under similar pressure, he went 17-for-21 (81 percent), despite Diggs' two drops.

He has proved himself accurate and tough since his first snap in purple. Sunday, he even completed three passes to Laquon Treadwell. That's two more catches than Treadwell had his entire rookie season, three more than he had previously this preseason and three more than Jarius Wright had Sunday.

With Michael Floyd suspended the first four games, Treadwell has an opportunity to become an important part of the offense, and a responsibility to justify the first-round pick the Vikings spent on him.

For all of the uncertainty about what a preseason performance means, Bradford and Treadwell's chemistry could prove important when the games matter, assuming the offensive line allows Bradford to remain upright long enough to cock his arm.

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