“The ‘Base Stealers’ and ‘Fly Catchers’ played an entertaining game of ball on the Park, Saturday afternoon, to the amusement and delight of a crowd of spectators, who fairly grew fat on laughter.” Hartford Daily Courant, October 14, 1867, p8
“Murnan and McGeary, the first two strikers, made clean hits for bases, and were each in turn thrown out while trying to steal to second. The throwing of Miller and the skill with which Battin handled the ball are deserving of special note, as the men who were put out in this manner are among the best runners and base stealers in the profession.” St. Louis Daily Globe-Democrat, September 24, 1875, p8
- Note: There are numerous mentions of the Hartford teams the Base Stealers and the Fly Catchers in the Courant between 1867 and 1869. They include items about games played as well as social events. (The first item noted above includes a box score.) A June 21, 1869 item is particularly noteworthy. (“The rumor that the ‘Red Stockings’ of Cincinnati, now on their triumphal Eastern tour, have challenged the famous Fly Catchers and Base Stealers of this city, is without foundation. They are not open to challenge this season.”) The team name is presumably a reference to the act of stealing a base, though the 1875 St. Louis article is the first I’ve found that specifically uses the term to refer to someone stealing a base.
Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1892 (New York Press, Aug. 7; Edward J. Nichols).