| John O'Donnell | |
| Birth Place: | Littlestown, Pennsylvania, U.S. |
| Bats: | Unknown |
| Throws: | Unknown |
| Debutleague: | MLB |
| Debutdate: | July 16 |
| Debutyear: | 1884 |
| Debutteam: | Philadelphia Keystones |
| Finalleague: | MLB |
| Finaldate: | July 16 |
| Finalyear: | 1884 |
| Finalteam: | Philadelphia Keystones |
| Statleague: | MLB |
| Stat1label: | Batting average |
| Stat1value: | .250 |
| Stat2label: | Home runs |
| Stat2value: | 0 |
| Stat3label: | Runs batted in |
| Stat3value: | 0 |
| Teams: |
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John O'Donnell was a 19th-century American Major League Baseball player. He played catcher in one game for the 1884 Philadelphia Keystones of the Union Association. His one game was played on July 16, 1884. He recorded one hit in four at-bats.