“Jube now came to the rescue and sent a ‘grass cutter’ over the field and landing the ball on the other side of the public square on an old man’s head, from which it rebounded into an alley, killing two chickens.” “Base Ball at Bungtown,” State Register (Des Moines, IA), August 7, 1867, p1
“Pike knocked a magnificent grass cutter into the right field, going to third base and afterwards home.” “Base Ball: Mutual, of New York, vs. Pastime, of Baltimore,” Baltimore American, August 28, 1867, p4
NOTE: The August 7th article is a satire, as evident in the description of a “grass cutter” landing on someone’s head, but is still a clear indication that the term was in use. The August 28th article is the earliest use of the term in an actual game description.
Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1870. “Parsell got 1st on hit, and home by the assistance of Decker, who made his 3d on a grass cutter to l.f.” (Flint [Mich.] Wolverine Citizen, Sept. 3; Peter Morris)