| Elmer Knetzer | |
| Position: | Pitcher |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | July 22, 1885 |
| Birth Place: | Carrick, Pennsylvania |
| Debutleague: | MLB |
| Debutdate: | September 11 |
| Debutyear: | 1909 |
| Debutteam: | Brooklyn Superbas |
| Finalleague: | MLB |
| Finaldate: | June 18 |
| Finalyear: | 1917 |
| Finalteam: | Cincinnati Reds |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 69-69 |
| Stat2label: | Earned run average |
| Stat2value: | 3.15 |
| Stat3label: | Strikeouts |
| Stat3value: | 535 |
| Teams: |
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Elmer Ellsworth Knetzer (July 22, 1885 – October 3, 1975) was a professional baseball player who played pitcher in the Major Leagues from 1909 to 1917. He played for the Brooklyn Dodgers, Pittsburgh Rebels, Boston Braves, and Cincinnati Reds.