Hugh's big NHL break came after the tragic death of Bill Barilko. Hugh had appeared in 13 games in the previous two seasons with the Leafs, but was a full time Leaf come the 1951-52 season. Hugh had an agreement with the Leafs that he would play part time as he slowly continued his studying of engineering at the University of Toronto at the same time. It is believed he put his studies aside in 1951-52 but that's why he appeared in only 13 games the previous two years.
Hugh returned to part time play the following two seasons though not entirely due to his studies. He was a very injury prone player, breaking his leg/ankle three times, his right arm three times, fracturing his skull and smashing his sinus cavity. He once took a Boom Boom Geoffrion shot to the face, cracking his jaw.
He was as rugged as he was tough, using his big size to unceremoniously welcome opposing skaters to the Leafs defensive zone. The noted shot blocker and poke checker was particularly good in 1955 when he finished 5th in Norris Trophy voting as the league's best defenseman.
Bolton played from 1954 through 1956 relatively injury free but early in 1956-57 he broke his leg yet again. He retired in 1957, tired of battling injuries and still looking to complete his University degree.