Regarding playing for two teams in one day -
 
Max Flack and Cliff Heathcote were traded between games of a doubleheader on 
May 30, 1922.  Flack played the first game for Chicago Cubs, Heathcote for 
the St. Louis Cards.  They were 
swapped between games and played for their two new teams in the second game.
 
Joel Youngblood played for the Mets in an afternoon game in 1982,
then in a night game for the Expos.
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