In , Oliva won his third AL batting title with a .337 average and led the league in slugging percentage (.546). These feats at the end of a skein of eight straight All-Star appearances that began his rookie season marked the high point of his career, as severe knee, leg, and shoulder injuries hampered his remaining playing days. His roommate Rod Carew often heard Oliva "moaning and groaning" and getting up to obtain ice for his sore knees during the night. He missed all but ten games of the 1972 season, which required season-ending surgery. Due to injuries and a 1973 American League rule change establishing the position, he became the Twins' designated hitter that spring and remained in that role his final four seasons.