By Tim Baffoe–

(CBS) When the Chicago Cubs and St. Louis Cardinals met in the National League Division Series last fall, there was some novelty to the playoff intensity, because the two had never faced off in the postseason before.

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Now as the teams begin their first regular-season series since then when they meet Monday night in St. Louis, a new vibe buzzes through the rivalry. A metamorphosis has occurred where this is no longer a lopsided matchup with one side’s fans assuming victory (rightly so) and the other side’s using these series as hopefully moral victories in an otherwise futile season.

Now it’s big-kid baseball. Two established teams — the Cardinals via their 21st century résumé and the Cubs via last year’s blossoming after seeds were planted by a new regime — are ready to jostle one another for NL Central supremacy now and for the rest of the decade. The baseball has changed the tone of Cubs vs. Cardinals.

For once, a season has begun with the Cardinals not getting the lion’s share of preseason national chatter and analysis. If you’re a Cubs fan, it’s nice to not be the underdog for once — but it’s also strange.

The respective distaste for one another is still there, of course. The fans don’t much care for one another. Cardinals fans perpetually delight in their rivals’ lack of jewelry and hardware, while Cubs fans milk the “Best Fans In Baseball” and “Cardinal Way” barf for all it’s worth.

But 2016 and the first meeting between these clubs brings a bit of a shift. The Cubs have won nothing to hang a titled Pedro Strop cap on, save for (the ultimately weak) bragging rights of winning that playoff series, and everyone knows preseason predictions and paper champs talk is cheap. The Cubs don’t yet deserve a respect reserved for winners. Still, a fan base’s attitude goes the way of its team.

What the Cubs are receiving (and maybe this is a form of respect) is obvious concern from the other side of the Mississippi River. Granted, members of the Cardinals are being asked about the Cubs and not bringing up the subject of “this is their year,” but it’s not like the Cubs are verbally fueling any of this. If anything, Cubs players and coaches go out of their way to not talk about expectations, but there’s a tinge of worry masked as bother out there across state lines.

First it was the severe undie-bunching over Jason Heyward’s benign words about signing with the Cubs. Then it was this year’s sick burn of not mentioning the Cubs by name. Cardinals manager and overly earnest teen comedy gym teacher Mike Matheny recently refused to let it pass his lips when asked about the Pittsburgh Pirates maybe being overlooked at the start of the season.

“Obviously, you hear everything about the ‘other team,’” Matheny said, according to the the St. Louis Post-Dispatch. “I don’t know if (the Pirates) have been slighted or not.

“Our guys would say that we have, but I imagine they’re saying the same thing because there’s so much noise coming out of the one team.

“That’s the beauty of it. They can say all they want to say but it doesn’t matter until you actually get out there and do it.”

Who that “other team” might be?

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“That’s open to interpretation,” Matheny said before presumably ironing a fine pair of slacks.

Yeah, so that’s high schoolish, but it doesn’t happen two years ago when the building Cubs were trying not to trip over their own feet. And what “noise” is emanating from the Cubs? This kind?

“If you ask me about the rivalry this year, I feel like I’m on the side that has a lot of work to do as far as being established in the playoffs,” Heyward said, via the Chicago Tribune. “They’ve got World Series championships. They’ve got division titles. We want to be established as a group in Chicago.”

Ugh, what an ego. Heyward truly will be deserving of boos this week when he takes the field.

But Cubs fans, rather than just hoping to catch some breaks while simultaneously wishing bad outcomes on the Cardinals, are filled with excitement and a sort of awkward pubescent discovery of a new self. This is a byproduct of a relaxed team attitude.

For the Cubs, these Cardinals series are no longer about being asked bland questions of historic franchises before getting swept in an equally miserable season or fans clinging to that lame Bears fan mentality of “If they just beat the Packers, it’s all worth it.”

“Just another series,” Cubs third baseman Kris Bryant told the Chicago Tribune. “That’s how we treat every series, (playing) a nameless, faceless opponent. That’s how we always try to approach things and not really worry about who we’re playing.”

Division wins are important, for sure, but for both sides those wins are about first place now and for the foreseeable future rather than mere hollow posturing in the media and Twitter barbs. And the feeling of entitlement is no longer tilted heavily in favor of one side.

The tone has changed, because the baseball is now very real. As the Cardinals have systematically sustained success for years, the Cubs have caught up.

The power structure in the NL Central has balanced. In turn, so has the mood on both sides of the rivalry. A Cubs-Cardinals series no longer exists in a vacuum in which winning two of three earns fans something for a week or two.

It’s not about bragging rights anymore. It’s about genuine superiority and serious business for both sides.

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Tim Baffoe is a columnist for CBSChicago.com. Follow Tim on Twitter @TimBaffoe. The views expressed on this page are those of the author, not CBS Local Chicago or our affiliated television and radio stations.