Usually a Red Sox-Yankees series comes with more than enough baggage — see Joe Kelly’s Fight Club, Bucky Dent, 1918, Don Zimmer throwdown, smack talk among fans, hype from the media for details.

And if it doesn’t, then actual baseball battles are being waged, like vying for the American League East title or preventing the other team from realizing some dream.

All summer, we thought this final regular-season series between the Red Sox and Yankees would mean everything, but in reality is barely means anything.

What’s very different about this get-together is the Red Sox and Yankees are only pretending to care about each other.

What’s weird is the teams share a common enemy now, a stranger-danger situation that poses a real threat in real time. That enemy is the Oakland Athletics.

The Yankees have to beat Oakland in a one-game playoff for the AL wild card in order to play the Red Sox in the Division Series.

If they can’t, then it’s up to the Red Sox to vanquish Oakland.

And that’s not going to be easy.

The Red Sox haven’t seen the A’s since May. The Sox have not played well against Oakland, losing four out of six times, and it’s a team that is a lot better now than it was then.

The Red Sox know the Yankees all too well. They are cramming in order to get ready for the A’s.

“Very athletic, just like their name,” said manager Alex Cora. “A lot different than May. Now they have (left fielder Nick) Martini, (center fielder Ramon) Laureano in the outfield. One thing they do is catch the ball. (Matt) Olson at first, he’s been great at first. (Second baseman) Jed (Lowrie) has been solid. (Shortstop Marcus) Semien has been amazing compared to previous years. And the third baseman (Matt Chapman), just don’t hit it that way. In the outfield, Laureano is a game-changer. He’s been great. They are more athletic. They can run. They can do a few things. A base hit to right field, they go first to third. It’s different.”

And the pitching?

“The bullpen, everybody has been talking about them — (Jeurys) Familia, (closer Blake) Treinen and all of those guys, they’re pretty solid. They’ve been struggling a little bit lately. They’ve been using them a lot because their starters are not going deep in games. A complete team and a tough one. I mentioned in May how uncomfortable they were and they made me look good as an analyst.”

Cora’s counterpart on the Yankees, Aaron Boone, arrived at Fenway very much looking beyond this series.

He can’t avoid the A’s, a team the Yanks have not fared well against either. They beat Oakland two out of three at Yankee Stadium in May, but at the beginning of this month, they lost two of three to the new-and-improved A’s in Oakland.

“The A’s, when they came and played us in May, a little bit of a different team but they had our attention then, we felt like they were a really good (team),” said Boone. “Obviously Lowrie at that time from the start has been having a great year for them, but the continued emergence of guys like Khris Davis, Chapman’s become a star, Olson over at first, just see strides Semien’s made, then the callups they’ve had, what (right fielder Stephen) Piscotty’s been doing, then they go out and really bolster the bullpen to add to Treinen and those guys. This is a team that if they get a lead, they can shorten that game on you. Oakland’s a really good team and a really dangerous team. We know we’ve got to play really well if we’re going to beat them.”

All of this prep work is brand new to Cora. He’s not complaining about any of it. But to be clear, twice the amount of work is involved because the Red Sox will not know until after Wednesday night’s game if they’re playing Oakland or New York.

That wasn’t the case at the end of last season, when the Red Sox played the Astros in the last four games of the regular season knowing they were going to be their postseason foe, too.

“It’s more work, because you’ve got to prepare for both of them,” said Cora, putting on his Astros bench coach cap, circa 2017, for a bit. “When we got here, it was a four-game series, we knew it was going to be them. They were still trying to win the East, but it was just a matter of time. You have plenty of time to prepare for them. It wasn’t just that week.

“Right now, we’ve been preparing for Oakland and the Yankees, but it’s two teams, two different teams, and the A’s are a lot different than the team we saw in May. It’s more work, but that’s what we’re getting paid for. Dig into the information and prepare for whoever we’re going to play.”