According to AL.com, Starr and his wife, Cherry, have kept the dark secret hidden away for more than 60 years.
The cover story the couple always used since 1954 was that Bart Starr was injured in a punting exercise before his junior year with the Crimson Tide.
Cherry Starr said her husband was badly beaten with a wooden paddle during initiation into the school's A-Club for varsity lettermen.
"He was hospitalized at one point in traction," Cherry Starr told AL.com. "That was in the days when they were initiated into the A-Club, and they had severe beatings and paddling. From all the members of the A-Club, they lined up with a big paddle with holes drilled in it, and it actually injured his back."
Starr, now 82, never disclosed the incident because he thought "it would make him look bad," his wife said.
"But his back was never right after that," Cherry Starr said. "It was horrible. It was not a football injury. It was an injury sustained from hazing. His whole back all the way up to his rib cage looked like a piece of raw meat. The bruising went all the way up his back. It was red and black and awful looking. It was so brutal."
Bart Starr has been in declining health following two strokes in 2014.
Starr played 16 seasons in Green Bay and led the Packers to the first two Super Bowl championships. He later became the Packers' head coach from 1975 to 1983.
"He was in so much pain constantly," Cherry Starr told AL.com. "They nearly tried anything."
One of Starr's Alabama teammates, tight end Nick Germanos, who also the Crimson Tide's senior captain in 1955 and served in the Marine Corps following graduation, described the beatings.
"It was hell," Germanos said. "Lord have mercy, it was a rough initiation."