Major League Baseball says it’s looking into any rules White Sox manager Ozzie Guillen might have violated by using Twitter to make derogatory comments about an umpire after being ejected.

Guillen was tossed Wednesday night for arguing balls and strikes with plate umpire Todd Tichenor in the first inning of Chicago’s game at Yankee Stadium. He then turned to Twitter to say the ejection was pathetic and it would cost him a pricey fine.

Baseball has a social media policy covering employees that applies to managers and coaches and prevents them from disparaging umpires. There also are guidelines that basically prohibit players, managers and coaches from communicating by electronic equipment from 30 minutes before a game until it ends.