Tim Wakefield sprays champagne on the Fenway Park crowd after the Red Sox clinched the 2003 wild card. Boston Globe/Getty Images

When the Boston Red Sox clinched a wild-card berth in 2003, Derek Lowe and a couple of teammates ran out of Fenway Park while still wearing uniforms and cleats. They took over a local bar, where they served beer to hysterical fans.

The new one-game playoff format has contenders wondering: Do we pop the Champagne or not? Daniel Barbarisi explains on Lunch Break. Photo: AP.

Lowe promises there will be no such revelry if his current team, the New York Yankees, win a wild-card spot this year. The party pooper: baseball's new playoff format.

Before this year, winning the wild card was akin to winning a division. Each league sent its three division leaders and a single wild-card team to the playoffs. Starting this season, each league has two wild-card winners who must duke it out in a one-game playoff to determine who goes on to what used to be considered the postseason's first round.

"What are they going to give you?" Lowe said. "A hat that says 'Wild-Card Winner' that you could lose the next day?"

The new system has upended the pennant race, forcing teams to try to win their divisions to avoid the one-game playoff. It also has raised an important question for players: When do we get to party?

Baseball players love to crank up the music, slap on goggles and spray the bubbly far more often than their peers in other professional sports. Football, hockey and basketball teams often hold off on the champagne until they reach the championship round.

But partying has long been the national pastime of the national pastime. Pro teams have celebrated with champagne since at least the early 1900s, said Major League Baseball historian John Thorn. The 1910 Philadelphia Athletics celebrated their World Series victory on their train ride home from Chicago with two cases of champagne and 1,000 cigars.

Ball clubs traditionally break out the bubbly after clinching a playoff spot. And after the divisional series. And after the league championship series. And after the World Series. That's four champagne celebrations for baseball's champs in about a month.

Atlanta's Jason Heyward gets doused after clinching in 2010. Associated Press

It is up to clubhouse managers to organize the festivities that have become increasingly choreographed over the years. Yankees clubhouse manager Lou Cucuzza makes sure to have enough champagne and plastic sheeting (to protect lockers and equipment) on hand for the days of possible clinching games.

"Usually as the rounds go further, the price of champagne goes up," he said. "But you're spraying it, so you're not going to spray Dom Pérignon."

Cucuzza said he won't start planning celebrations in earnest until about a day before the potential big game. He doesn't expect the Yankees—who could win either the American League East division or a wild-card spot—to go crazy if they have to settle for the latter. "It shouldn't be that big of a celebration because we're expected to go in, but we'll have something for the younger kids," he said.

Many players say they might not figure out how to celebrate until they clinch a wild-card spot. The closest precedent for this conundrum comes from 1995, the first year that baseball added the wild-card teams and an extra round of the playoffs.

That year, the Yankees weren't sure whether to celebrate the day they clinched the wild card. They walked into the clubhouse and found baseball caps commemorating their achievement.

"There was a little bit of confusion," said David Cone, a starting pitcher on that team. "We put on the hats, and we talked about it, and then we asked (first baseman) Don Mattingly. And we said, 'You know what? It's his first trip to the postseason,' so we did." Cone said the team got some beer and had a subdued party.

Current players on wild-card contenders are in two camps. The first says they should postpone any fiestas until after the wild-card playoffs. The second argues that an extra postseason round is an extra reason to party.

Put David Ross in the latter category. "The grind of the season is hard enough," said the Atlanta Braves catcher. "That's considered the playoffs, so you celebrate it. Then you go get 'em for one game, and if you win it, you celebrate that."

Many players say they should commemorate each occasion because they might never reach the playoffs again, even if the postseason might mean only one extra game. But the answers differ from team to team.

"Here, I don't think I'll be running down any streets," Lowe said. "When you're with New York, or a St. Louis, or a Boston, it's expected you make the playoffs."

There is a different sentiment in Baltimore, where the Orioles haven't made the postseason since 1997.

"I'd be all for celebrating," said Jason Hammel, a starter for the Orioles, who are in position to earn a wild-card berth. "It's been a long time since a team here has been in meaningful games in September."

One spoilsport is the postseason schedule. The wild-card playoffs take place just two days after the season ends. That isn't counting possible tiebreaker games to determine a wild-card winner. Teams might have to play the wild-card game the day after the regular season.

There would be no champagne in that case, Lowe said. "Shake some hands, kiss some babies and off you go. You could literally be having to fly all the way across the United States."

—Jared Diamond contributed to this article.

Write to Daniel Barbarisi at Daniel.Barbarisi@wsj.com and Stu Woo at Stu.Woo@wsj.com