Hiya -- I stumbled across this page from Google when futzing with early baseball history research and wanted to point out that "Sleepy Hollow" here almost certainly refers to a place in Concord, MA rather than the famed New York location. It was a specific spot in Concord that was turned into a cemetery and is where Thoreau and his family are now buried (amongst other famed writers!).
But I'm sure many ballgames were being played in NY/tristate area before the legendary one on Hoboken's Elysian Fields, though! Cheers