#4 Keith Hernandez
While he is more closely associated with the Mets, Keith Hernandez had a pretty incredible stretch with the Cardinals, who drafted him in 1971.
He began his career with the Cards from 1974-1983. He was an All-Star in 1979 and 1980 with the Cardinals and earned the Gold Glove at first base for the Cardinals in 1978 - 1983. He also won the Silver Slugger award in 1980. Hernandez was the National League MVP in 1979.
During his time with the Cardinals, Hernandez hit .299/.385/.488 with an OPS of .833. He had 265 doubles, 50 triples, 81 home runs, and 595 RBI In the 1982 World Series against the Brewers, and he hit .259/.355/.444 with an OPS of .799 with four walks, seven hits, two doubles, a home run four runs scored and eight RBI.
The Cardinals traded Hernandez to the Mets in 1983 for Neil Allen and Rick Ownbey. Hernandez had many disagreements with manager Whitey Herzog. He has since said that his drug use was part of why he was traded from the Cardinals. Imagine if he hadn't used illicit drugs and stayed with the Cardinals longer. What a legend he could have been for the team.
He was elected by the fans to the Cardinals Hall of Fame in 2021.