Jewish baseball fans have created an exhaustive list of Jewish players. They missed Monte Pfeiffer.

For the first time in decades, a long forgotten major league baseball player has been posthumously identified as Jewish.

Monte Pfeiffer, who played a single game for the Philadelphia Athletics some 112 years ago, had vanished into baseball obscurity - until a sharp-eyed Yankees fan uncovered a surprising truth written in Hebrew. The discovery, rooted in dusty box scores, old newspaper articles and genealogical detective work, adds Pfeiffer to the rarest of rosters: Jewish major leaguers.

"It's really like fishing: You throw out your line, and nothing, nothing, nothing," said Zak Kranc, a 27-ye...