Major League Baseball ( MajorLeagueBaseball (MLB) is the highest level professional baseball league in the world, and is one of the four major professional sports leagues in North America, along with, MLB was founded in 1903, there are 30 participating teams, the famous teams include the New York Yankees, Philadelphia Phillies, Boston Red Sox, etc., the famous stars include Roy Halladay, Clay Kershaw, Justin Vermeulen and the New York Yankees. The teams include the New York Yankees, Philadelphia Phillies, Boston Red Sox, etc. Famous players include Roy Halladay, Clay Kershaw, Justin Verlander, etc.