The young pitcher reported to the Giants' farm club in St. Cloud, Minnesota, where he posted a 9-5 win-loss record. At the end of the 1958 season Perry, who wished to explore a college career, enrolled in Campbell Junior College in Buies Creek, North Carolina. At six-foot-four, Perry had been admitted on a basketball scholarship, but Perry was soon compelled to leave the school after the Giants decreed that he could not play basketball while a member of their organization.
So Perry took to the road, following his franchise into the minor leagues. Four years of developing his arm in the minors led him to San Francisco, where in 1962 Perry was given his first shot at a Major League game. He won three games for the Giants before being sent back to Tacoma, Washington, to complete the '62 season. But by 1963 Perry was back in San Francisco in what he described as his worst season. In thirty-one games he posted only one win, with a relatively high 4.03 earned-run average (ERA).
The year 1964 turned out to be a watershed one for Perry: it was the year he learned the spitball. Illegal in the majors, a spitball has the pitcher coating the ball with saliva or some other slick substance. The doctored ball will thus become an extreme "sinker" as it approaches the plate. Bob Shaw, a spitball expert, had joined the Giants organization and instructed Perry in the basics, which include how to hide the presence of the banned ball from "four umpires, three coaches, and twenty-five players on the field as well as spying executives up on the box seats," as he later wrote in his autobiography. The key, Perry noted, was in the use of the fingers: "Those days you were allowed by the rules to lick your fingers as long as you wiped them dry. A great decoy was going to the resin bag after licking your first and second fingers. You bounced the dusty bag all around in your pitching hand, but those two fingers never got a touch of dry resin."