The earliest known references to jazz are in the sports pages of various West Coast newspapers covering the Pacific Coast League, a baseball minor league. The earliest example, found by New York University librarian George A. Thompson, Jr. in 2003, is from the Los Angeles Times on April 2, 1912, referring to Portland Beavers pitcher Ben Henderson:
BEN'S JAZZ CURVE.
"I got a new curve this year," softly murmured Henderson yesterday, "and I'm goin' to pitch one or two of them tomorrow. I call it the Jazz ball because it wobbles and you simply can't do anything with it."


A more lasting influence emerged in 1913, in a series of articles by E.T. "Scoop" Gleeson in the San Francisco Bulletin, found by researchers Peter Tamony (who carried out the pioneering research in this area) and Dick Holbrook, that likely were instrumental in bringing jazz to a broader public. These initial articles were written in Boyes Springs, California, where the San Francisco Seals baseball team was in training. In the earliest reference, on March 3, 1913, jazz was used in a negative sense, to indicate that disparaging information about ball player George Clifford McCarl had turned out to be inaccurate: "McCarl has been heralded all along the line as a 'busher,' but now it develops that this dope is very much to the 'jazz.'"