Sentence:  Mantle , the bull-necked blond switch-hitter , had one sensational <WSD>triple-crown</WSD> season , 1959 , when he batted .365 and also led the American League in home runs , 52 , and RBIs , 130 . 
Meaning of the word marked with <WSD> tags:  a season of baseball during which a player wins the triple crown