Mike Celizic

The American League East is used to the big, bad team with great pitching, a super bullpen, clutch hitting up and down the lineup and a swagger in its gait grabbing the division by the throat in September and not letting go.

It’s just not used to that team suiting up in uniforms that aren’t decorated with pinstripes.

The Red Sox aren’t just coming. They’re banging at the door of the division lead, and whether they grab it right now from the amazing Rays or wait another week to get the job done isn’t important. What is worth taking a moment to gawk at in wonder is how quickly and emphatically Boston has asserted itself.

As recently at Aug. 31, Boston seemed all but locked into the AL wild card. They were 5 1/2 games behind Tampa, which had held on to first place for two months, shrugging off all challengers. They were also comfortably ahead of Minnesota in the wild-card race.

In less than two weeks, it all changed. Boston went on a winning tear, Tampa got slapped around in Toronto and New York, and now it’s a two-team death match with first place in the East and possibly home-field advantage through the playoffs for the taking.

What Tampa’s doing is one of the great stories that baseball has ever given us. But they’re a young team that doesn’t know what they’re not capable of, a team that’s caught lightning in a bottle for the first time in franchise history.

What Boston is doing is just as impressive — maybe more so. The Red Sox are doing the hardest thing in sports: living up to expectations.

They’re coming off their second championship in four seasons, and with what they’re doing this year, it’s fair to start talking about them the way we used to talk about the Yankees. They’re a dynasty now, a powerful team that overcomes injuries, adversity and other teams that think they can knock them off.

You don’t become a dynasty because a bunch of pundits with laptops say you are. You get there by doing it on the field.

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The Red Sox were such an outfit 90 years ago. Now, with their two titles and their performance this year to back it up, they are that again.

There’s an aura about such teams. Call it swagger if you will, but it’s more than just the insouciant self-confidence that term implies. Opposing teams talk about it as if it were a palpable thing. They come into the home field of a dynasty and they go weak in the knees telling reporters about what a special place it is.

In the days when Boston was a lovable group of losers, opposing teams gushed about Fenway Park, but the discussion involved the quaint contours, the looming Green Monster, the Pesky Pole and everything else that makes the cramped old bandbox baseball’s crown jewel.

Today, opposing teams talk more about how hard it is to play there, the way they used to talk about Yankee Stadium. There are ghosts of past greatness collecting in the nooks and crannies of the old ballpark, a history of success that players feel.

Joe Maddon, the Rays manager, talked about Fenway’s “vibe” when his team arrived on Monday for the three-game set that concludes Wednesday.

“This is just a tough place to play,” Maddon told reporters. “It’s a combination of them being a very good ballclub and the tradition and the standings and the fan base. … They have the tradition, the World Championships, and they’ve got a very good fan base.”

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That word “tradition” is the telling one. Just a few years ago, if you said “tradition” in connection with the Red Sox, you were talking about seventh-game losses in October. Now, Maddon uses it to underline just how tough the Red Sox are.

It’s not easy what they’re doing. Their pitching is coming together and the bullpen has been nearly impenetrable — at least it was before Jonathan Papelbon blew the lead and the ballgame Tuesday night. Coco Crisp has been impossible to get out, Jason Bay has more than replaced Manny Ramirez and the offense is clicking. The Red Sox have put it all together when it matters most.

They’ve got another three games in Tampa next week, and it’s likely by the end of that series, the East will be pretty much settled. Either way, the Red Sox go to the playoffs, but it will be instructive to see what they do away from Fenway, where their record is a pedestrian 36-39.

Dynastic teams pack their aura and swagger along with the bats, balls and gloves when they go on the road. And when autumn looms on the calendar, they play their best. The Red Sox are doing that. They’re the big, bad team from the AL East now, the team nobody wants to face.

And they’re coming after first place.