McCovey returned to the Giants in 1977 without a guaranteed contract, but he earned a position on the team. With Hank Aaron and Frank Robinson having retired at the end of the 1976 season with 755 and 586 home runs respectively, McCovey began 1977 as the active home run leader with 465. That year, during a June 27 game against the Cincinnati Reds, he became the first player to hit two home runs in one inning twice in his career (the first was on April 12, 1973), a feat since accomplished by Andre Dawson, Dale Murphy, Jeff King, Alex Rodriguez, and Edwin Encarnacion. One was a grand slam and he became the first National Leaguer to hit seventeen. At age 39, he had 28 home runs and 86 RBIs and was named the Comeback Player of the Year.