on an infield single by Devin Mesoraco off Pittsburgh Pirates relief pitcher Mark Melancon during the ninth inning a baseball game in Pittsburgh on Friday, Sept. 20, 2013. The Reds won 6-5 in 10 innings. (AP Photo/Gene J. Puskar)

Cleveland Indians starting pitcher Danny Salazar throws during the first inning of a baseball game against the Kansas City Royals, Wednesday, Sept. 18, 2013, in Kansas City, Mo. (AP Photo/Charlie Riedel)

St. Louis Cardinals manager Mike Matheny (22) and pitcher Adam Wainwright wave their caps in appreciation of the fans after their final regular season game against the Chicago Cubs, Sunday, Sept. 29, 2013, at Busch Stadium in St. Louis. The Cardinals won 4-0. (AP Photo/St. Louis Post-Dispatch, Chris Lee) EDWARDSVILLE INTELLIGENCER OUT; THE ALTON TELEGRAPH OUT

SECRET WEAPON: Looking for anfall how risky it can be to let an entire season tilt on one play. Umpire Sam Holbrook's infield fly call sent fans running for the rule book and set off a huge debate on what constitutes "ordinary effort." A bad hop, a blooper or a missed ump's call such as the one in the Rays-Rangers game — anything can make the difference when it gets down to one game.

SUCCESS RATE: Five wild-card teams have won the World Series, including the 2011 Cardinals and the 2004 Red Sox. But that was before baseball changed the playoff format last year, creating a wild-card playoff. MLB wanted to put a premium on winning a division title and make it harder for wild cards to advance by adding the extra game.

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