Philip Humber of the Chicago White Sox has pitched a perfect game in a 4-0 win over the Mariners in Seattle.
Only 20 other pitchers have tossed perfect games, in which no opposing batter reaches base, in Major League history, according to MLB.com.
It was the first no-hitter of the 2012 season.
Until Humber's gem, Oakland's Dallas Braden had the most recent perfect game, on May 9, 2010, against the Tampa Bay Rays. The last White Sox pitcher to throw a perfect game was Mark Buehrle against the Rays on July 23, 2009.