Dennis grew up in Tucson Arizona where he graduated from Canyon del Oro high school. During his senior year he was the Southern Arizona player of the year, All-State, Mizuno All-American and drafted by the NY Mets.  In his first 2 years of college he attended Pima Community College and was drafted by the SF Giants but did not sign and transferred to the University of Arizona.  After one year there he was drafted and signed with the Florida Marlins.  Dennis played 7 years in the Marlins organization, then played winter ball for the Venados de Mazatlan in Mazatlan Sinaloa, Mexico. He signed a free agent contract with the Cubs and hit .357 in big leauge spring training.  The next year Dennis signed with the Boston Red Sox and retired after spring training.