Lyle was first signed as an amateur free agent by the Baltimore Orioles on June 17, 1964; however, he never played a game for the Orioles. On November 30 of the same year, he was drafted by the Boston Red Sox from the Orioles. He first joined the Red Sox as a player on July 4, 1967, during their "Impossible Dream" season. Lyle missed the 1967 Red Sow World Series because of an injury. By the 1969 season, he would emerge as the Red Sox' top reliever. On March 22, 1972, he was traded to the New York Yankees in exchange for first baseman Danny Cater and a player to be named later (Mario Guerrero).