This is a list of Mexican football transfers in the Mexican Primera Division during the winter 2011 transfer window, grouped by club. The 2011 winter transfer window for Mexican football opened on December 1 and will close at 23:00 on December 21, 2011 for the national market and on December 31, 2011 for the international one. Football has been played professionally in Mexico since the early 1900s. Since 1996, the country has played two split seasons instead of a traditional long season. There are two separate playoff and league divisions. After many years of calling the regular seasons as "Verano" (Summer) and "Invierno" (Winter); the Primera División de México (Mexican First League Division) have changed the names of the competition, and has opted for "Apertura" (opening) and "Clausura"