| Louis Graff | |
| Position: | Catcher |
| Bats: | Unknown |
| Throws: | Right |
| Birth Date: | July 25, 1866 |
| Birth Place: | Philadelphia, Pennsylvania, U.S. |
| Death Place: | Bryn Mawr, Pennsylvania, U.S. |
| Debutleague: | MLB |
| Debutdate: | June 23 |
| Debutyear: | 1890 |
| Debutteam: | Syracuse Stars |
| Finalleague: | MLB |
| Finaldate: | June 23 |
| Finalyear: | 1890 |
| Finalteam: | Syracuse Stars |
| Statleague: | MLB |
| Stat1label: | Batting average |
| Stat1value: | .400 |
| Stat2label: | Home runs |
| Stat2value: | 0 |
| Stat3label: | Runs batted in |
| Stat3value: | 3 |
| Teams: |
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Louis George Graff (July 25, 1866 – April 16, 1955) was a 19th-century American Major League Baseball catcher with the Syracuse Stars of the American Association. Nicknamed "Chappie", he appeared in one game for the Stars on June 23, 1890 and recorded 2 hits in 5 at-bats with 3 RBI.