The next season, he posted career-highs in home runs (9), runs (59), runs batted in (41) and fielding percentage (.991) but hit for only a .229 batting average in 148 games.[1] In 1974 and 1975 he averaged .291 each season.[1] In October 1976, Rader was traded to the St. Louis Cardinals where he served as a reserve catcher working behind Ted Simmons during the 1977 season.[1][5]
After one year with the Cardinals, he was traded to the Chicago Cubs in December 1977.[5] Rader became the Cubs' regular catcher during the 1978 season, playing in 114 games but, only managed to post a .203 batting average and, in February 1979, he would be traded to the Philadelphia Phillies.[1][5] He served as a third string catcher with the Phillies, backing up Bob Boone and Tim McCarver. Rader would be traded a final time in March 1980 to the Boston Red Sox where he backed up regular Red Sox catcher, Carlton Fisk.[5] In November 1980, the Red Sox granted Rader free agency. He signed with the California Angels in February 1981 but was released two and a half months later.[1]