The Giants have seen a fair share of rookie phenoms pass through the organization and make big splashes at the outset of their careers. Here’s a look back at the six Giants to win the Baseball Writers’ Association of America’s National League Rookie of the Year Award, which was established in 1947:

Willie Mays, 1951
Mays began his professional baseball career at 16 with the Birmingham Black Barons of the Negro Leagues and eventually caught the eye of the New York Giants, who purchased his contract in 1950. He reached the Majors the following year, but he endured a slow start as a 20-year-old rookie, going hitless in his first 12 at-bats before finally breaking through with a home run off future Hall of Famer Warren Spahn. The Say Hey Kid never looked back, batting .274 with 20 home runs and 68 RBIs over 121 games to become the first Giant to win NL Rookie of the Year honors.

Orlando Cepeda, 1958
A native of Ponce, Puerto Rico, Cepeda received a $500 bonus after signing with the Giants as an amateur free agent in 1955. Three years later, he broke into the Majors and emerged as a 20-year-old sensation for the Giants, who were playing their inaugural season in San Francisco. The slugging first baseman quickly endeared himself to fans on the West Coast, unanimously winning the NL Rookie of the Year Award after batting .312 with 25 home runs and 96 RBIs over 148 games.

Willie McCovey, 1959
One year after Cepeda burst onto the scene, the Giants witnessed the arrival of yet another young hitting phenom in McCovey, who forced his way onto the Major League roster after batting .372 with 29 homers and 92 RBIs over 95 games at Triple-A Phoenix. The lanky 21-year-old from Mobile, Ala., debuted with the Giants on July 30, 1959, when he went 4-for-4 with two triples against Phillies ace and future Hall of Famer Robin Roberts. It was a sign of things to come, as McCovey batted .354 with 13 home runs and 38 RBIs over 219 plate appearances to unanimously capture the NL Rookie of the Year Award and give the Giants back-to-back winners.

Gary Matthews, 1973
A 1968 first-round Draft pick, Matthews appeared in 20 games for the Giants as a September callup in 1972 before becoming an everyday player the following year. He made the most of his first extended opportunity to compete in the Majors, hitting .300 with an.812 OPS, 12 homers and 17 stolen bases en route to winning NL rookie honors.

John Montefusco, 1975
Montefusco debuted with the Giants on Sept. 3, 1974, at Dodger Stadium after being summoned to relieve veteran Ron Bryant, who was chased from the game without retiring a single batter. Still, a 24-year-old Montefusco rose to the occasion, allowing one run on six hits over a nine-inning relief stint while walking and homering at the plate to carry the Giants to a 9-5 win over the Dodgers. Montefusco saw action in only seven games in 1974, but he went 15-9 with a 2.88 ERA over 243 2/3 innings in 1975 to become the first Giants pitcher to be named NL Rookie of the Year.

Buster Posey, 2010
Posey, the fifth overall pick of the 2008 Draft, earned a September callup with the Giants in 2009, but he didn’t truly arrive until the following season. Posey spent almost two months at Triple-A Fresno in 2010 before he was promoted to play first base and bolster San Francisco’s struggling offense. He took off after the Giants traded Bengie Molina to the Rangers in July and installed the 23-year-old rookie as their everyday catcher. Posey went on to hit .305 with an .862 OPS, 18 homers and 67 RBIs over 108 games, leading the Giants to their first World Series title since moving to San Francisco in 1958.