6. Johnny Mize (1942-1949)
Wins Above Replacement: 28.3
Mize played only five seasons with the Giants. After his first season with the team in 1942, he spent the next three years fighting overseas in World War II. The Hall of Famer went to the All-Star game nine times in his career and four times with the Giants. In his first four years with the Giants, he also earned MVP votes and finished third in 1947. That year he was a WAR of 7.1 and finished that season with a slashline of .302/.384/.614 for an incredible OPS of .998. He also had career highs in home runs and RBI’s with 51 and 138 respectively.
Overall, he played 655 career games at first base in New York and had a career slashline with the Giants of .299/.389/.549 for an OPS of .938.