PREVIEW-Baseball-Single-game showdowns launch MLB postseason (Reuters)

NEW YORK, Oct 4 (Reuters) - Single-game playoffs have produced some great moments in Major League Baseball (MLB) and a new postseason format for 2012 now guarantees two of them, with Texas, Baltimore, St. Louis and Atlanta all on the spot. With a second wildcard team added in both leagues, the postseason opens Friday with one-game showdowns between the World Series champion St. Louis Cardinals and host Atlanta Braves, as well as last season's American League champion Texas Rangers against the visiting Baltimore Orioles. ...Elton John David Letterman Phil Mickelson J.K. Rowling Brad Pitt Peter Jackson Dr. Phil McGraw Jay Leno Celine Dion Kobe Bryant