If you go to Baseball Reference and look through some box score from some old 1907 New York Highlanders’ games, you will come across the name Rudy Baerwald.
Baerwald was an outfielder who played in 17 late season games for the then-Highlanders in 1907 and then never appeared in the major leagues again. He didn’t do anything especially notable and would be sold to a minor league team the next season and would play a further 10 years in the minors.
However, there is something strange about Baerwald. If you go to, say, the New York Times articles about the game he appeared in, you won’t find him listed in those box scores.