I randomly thought of this poem the other day, and have found two older references. The first stanza was printed more or less verbatim as above in Madison's Wisconsin State Journal, of October 13th, 1949 (p. 19). And John E. Spalding's A century of sports in Santa Clara County, 1900-1999, p. 52 credits it to the San Francisco Chronicle's Dick Friendlich. I can't access the whole article (see a snippet here) but his run of it is the earliest I've found, printed in the September 6th, 1949 edition.