Leonard Gary Gabrielson was an outfielder in Major League Baseball. He graduated from the University of Southern California and played in the majors from 1960 through 1970, initially signing with the Milwaukee Braves in 1959 as an amateur free agent.
After parts of three seasons with the Braves, he was traded to the Chicago Cubs on June 3, 1964, in exchange for catcher Merritt Ranew and $40,000. Two weeks later, the Cubs traded their starting right fielder Lou Brock to the St. Louis Cardinals, and installed Gabrielson as Brock's replacement.
He lasted less than a year with the Cubs, moving on to the San Francisco Giants in a five-player deal on May 29, 1965. The Giants received Gabrielson and catcher Dick Bertell, surrendering fading stars Harvey Kuenn and Ed Bailey and pitcher Bob Hendley. Gabrielson gradually worked his way into a role as the team's starting left fielder, a role he successfully defended in spring training of 1966, beating back a challenge by star Orlando Cepeda, who had been displaced from first base by Willie McCovey.