Two wild card teams will be added to Major League Baseball's playoffs no later than 2013, the same year the Houston Astros will begin play in the American League.

Commissioner Bud Selig announced Thursday that baseball's owners unanimously approved Jim Crane as the Houston Astros' owner. As part of his agreement to buy the club, Crane will shift the Astros to the AL after 2012, creating two 15-team leagues.

"It's a historical day," said Selig, whose new format ensures that an interleague game will be contested "from opening day on."

Selig did not offer specifics on the schedule or playoff format, but said his committee for on-field matters favors the one-game playoff among wild-card teams in each league, saying it would be "dramatic." The additional wild cards could be added for the 2012 season, but will be in place by 2013 for sure.

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Crane's Astros will move from the NL Central to the AL West after next season, a result he originally was not pleased with due to the bevy of West Coast road games added to the Astros' TV schedule. Crane is to receive a refund of approximately $70 million of his $660 million purchase price to mitigate the potential crimp on the Astros' local TV ratings.

"I was in the air freight business," Crane told reporters at baseball's general managers' meetings. "I've always flown a lot ... we'll be flying a lot.''

The Astros' move creates six divisions with five teams, removing the anomalies that were the AL West (four teams) and NL Central (six teams).

If the 2013 playoff format had been in place this season, the Tampa Bay Rays and Boston Red Sox would have met in a one-game playoff, with the winner advancing to the AL Division Series. In the National League, the St. Louis Cardinals and Atlanta Braves would have met in a one-game playoff.

The new format would have doused much of the last-second drama that created, in some observers' eyes, the best final day of the regular season in baseball history this past September.

That a 162-game season could also come down to the vagaries of a one-game playoff has also raised some concerns.

There will be upsides to the format, as well.

There will be a greater incentive for teams to win their own division, so as to avoid the one-game playoff. In recent years, clubs have expressed ambivalence, at best, over going all-in to win a division title when a wild-card berth was available.

AL Cy Young winner Justin Verlander, for one, tweeted as much:

I like concept of adding wild card team for playoffs. Gives advantage to teams winning their division - don't have to play in 1 gm playoff

GMs and owners seemed as unanimously in favor of the expanded playoffs as they were the vote to approve Crane.

Said Washington Nationals GM Mike Rizzo: "When we first went to a wild-card, I was skeptical. It's become so wildly successful, I think this will be equally as successful. All of the baseball guys are for it.''

As for the Astros, mathematically their odds of winning their division theoretically got better, moving from a six-team to a five-team division. However, they're leaving behind middle-market clubs such as the Pirates and Reds for the big-money Rangers, Angels and Mariners, along with the once-savvy A's.

Contributing: Bob Nightengale in Milwaukee