After checking into the rehab center, Porter became a born-again Christian, married, and became a spokesman for the Fellowship of Christian Athletes. His production on the field declined after rehab, and he never again approached his 1979 levels. He went on to play in three World Series—in 1980 with the Royals and in 1982 and 1985 with the St. Louis Cardinals. Porter won both the 1982 National League Championship Series Most Valuable Player Award and the 1982 World Series MVP Award. At the time, Porter was only the second player in baseball history to win both awards in a single postseason; Willie Stargell of the Pittsburgh Pirates won both awards in 1979. After the 1985 season, the Cardinals released Porter, and he wound up his career with two seasons with the Texas Rangers as a part-time player. He appeared in his final major league game on October 4, 1987 and retired at the age of 35.