BOSTON — The A’s season already is a success.

When it began, Oakland had the majors’ lowest payroll and there were four perceived AL superpowers.

When the regular season ends Sunday, the A’s will be in the playoffs with those four superpowers — the Yankees, Red Sox, Indians and Astros. You could describe Oakland as party crashers. That would suggest the A’s did not earn their way beyond the playoff velvet rope.

They did.

But much like the beginning of the season, the expectations again are low for them. Of course, they want to win Wednesday and keep advancing, to turn successful into historical. However, no losing score in the wild-card game would depreciate the A’s 2018.

That is not true for the Yankees.

A scout I talked to recently put the AL portion of the playoffs in perspective: “There are going to be a lot of disappointed teams and fan bases because there are four really, really good teams, and as they are picked off one by one, they are each going to be devastated because they are built to win right now and are good enough to win right now.”

This is why the Yankees should start Luis Severino in the wild card — because they don’t have to win one game in October. They have to win 12.

Yes, yes, of course, Wednesday is a sudden death and you are supposed to have blinders on when it is survive-and-advance and look at nothing else. In that scenario, you go with J.A. Happ because he has been the Yankees’ best starter for the past two months and is the most likely member of the rotation to avoid a blow up that imperils the team from the outset.

Severino blew up in the wild-card game last year. He allowed three runs and lasted one out, but the Yankees survived because Didi Gregorius hit a three-run homer in the bottom of the first — their biggest hit of the season — to re-stabilize the game and the Yankees out-talented the Twins from there.

But Oakland is not Minnesota’s twin.

The 2017 Twins were deadline sellers who essentially fell into the second wild card with 85 victories because no one else wanted it. The 2018 A’s began Saturday with 96 wins — more than any NL team. They hit homers, play strong defense (especially in the outfield and third base) and most important mimic the Yankees in bullpen depth and quality.

Falling behind the A’s will not be like falling behind last year’s Twins. Consider in early August this year’s Twins traded their closer, Fernando Rodney, to the A’s, where he is perhaps their sixth bullpen choice.

So why start Severino? Because I think the difference is not great enough between him and Happ that the Yankees should fixate on one win rather than the big-picture 12. And the survivor Wednesday gets Game 1 at Fenway 48 hours later. Happ has been terrific against Boston, and if Severino starts the wild-card game and the Yanks win, then Happ would be lined up for Games 1 and 5 against Chris Sale, who has not looked like Chris Sale for a while now.

Plus, if Severino flourishes in the wild card — and in his past three starts he has a 2.04 ERA and 18 strikeouts in 17 ²/₃ innings — I could see it uplifting him for the whole month. And remember, the Yankees’ mission statement is not just 3-4 hours against Oakland, but some combination of Boston, Cleveland and Houston just to get to a World Series.

I know that on Sept. 4, Happ held the A’s to one run on two hits over six innings in Oakland, and the next day Severno was blasted for six runs in 2 ²/₃ innings. I know Happ has been better than Severino the past two months. But I also know the A’s power is predominantly righty and that Severino has been better against righties this year than Happ.

I also know whether it is Severino or Happ the leash will be short — Chad Green will be warming at the first indication of trouble, just like last year against the Twins. Severino becomes a more interesting weapon, told to go as hard as he can for as long as he can, whether it’s three innings, four, five, whatever. No expectation of 100-plus pitches and seven innings. The Yankees’ best relievers are all pitching in this game, unless it is a blowout one way or the other.

The question is who gets the ball to those relievers. With the Yanks having clinched the wild-card home field Friday, Aaron Boone announced Severino will not start Sunday. That leaves him an option for Wednesday. So is Happ. So is Masahiro Tanaka. So is a bullpen game, perhaps led off by Green.

I would go with Severino. Because for the Yankees, the postseason is about more than Wednesday.