10. Dick Dietz (1966-1971)
Wins Above Replacement: 11.6
Dietz played six seasons with the Giants. He went to the All-Star game in 1970 and finished that season with a slashline of .300/.426/.515 for an OPS of .941.
Overall, he played 563 career games at catcher in San Francisco and had a career slashline with the Giants of .262/.384/.431 for an OPS of .815.