Hampered by terrible pain in his left knee during the 1960–61 NHL season, Plante was sent down to the minor league Montreal Royals. Torn cartilage was found in his knee, and the knee was surgically repaired during the summer of 1961. The next season Plante became the one of seven goaltenders to win the Hart Memorial Trophy – he also won the Vezina Trophy for the sixth time. The 1962–63 season was unsettling for Plante. His asthma had worsened, and he missed most of the early season. His relationship with his coach, Toe Blake, continued to deteriorate because of Plante's persistent health problems. Later, Plante was at the center of a major controversy when he claimed that net sizes in the NHL were not uniform, thus giving a statistical advantage to goaltenders playing for the Chicago Black Hawks, Boston Bruins, and New York Rangers. His claim was later confirmed as the result of a manufacturing error.