How old were they?

Rube Foster

P · Born January 5, 1888

Age in each postseason series

1. 1915 World Series (October 8, 1915), Red Sox vs Phillies 4–1: 27 years, 276 days
2. 1916 World Series (October 7, 1916), Red Sox vs Robins 4–1: 28 years, 276 days

Age in each season

1. 1913 (Red Sox): 25 years, 86 days to 25 years, 269 days
2. 1914 (Red Sox): 26 years, 86 days to 26 years, 269 days
3. 1915 (Red Sox): 27 years, 86 days to 27 years, 269 days
4. 1916 (Red Sox): 28 years, 87 days to 28 years, 270 days
5. 1917 (Red Sox): 29 years, 86 days to 29 years, 269 days