Alvarez becomes the first baseball player to carry the flag for the U.S. The sport returned to the Games at the request of Japan after being absent from the previous two Olympics.
He made his major league debut last year with the Miami Marlins, but has been in the minors this year. If the U.S. baseball team were to medal, he'd be the only the third American to medal in both the Winter and Summer Games, joining Eddie Egan (boxing and bobsled) and Lauryn Williams (track and field and bobsled).
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