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A perfect game is defined by Major League Baseball as:

An official perfect game occurs when a pitcher (or pitchers) retires each batter on the opposing team during the entire course of a game, which consists of at least nine innings. In a perfect game, no batter reaches any base during the course of the game.

There were 20 of these pitching performances before today, with Philip Humber joining that club as the 21st pitcher to perform such a feat. He helped lead the Chicago White Sox to a 4-0 victory over the Seattle Mariners.

He only needed 96 pitches to get the job done and struck out nine along the way. This may be one of the more unlikely pitchers to do this since he has never thrown a complete game in his 29 career starts.

Now that he has accomplished this feat, the question that is asked is what's next?

Here is a breakdown of how the other 20 perfect game pitchers have performed in their next starts and over the course of their careers.