Ross "Rip" Hawkins, the Vikings' leading tackler in each of their first four seasons, was one of the four former Vikings among the 111 deceased NFL players whose brains were studied by researchers from Boston University and the VA Boston Healthcare System as part of the report published Tuesday in the Journal of the American Medical Association.

The other three, whose names were released on Wednesday, were Wally Hilgenberg, who played linebacker for the Vikings from 1968 to '79; Gerry Huth, who played guard from 1961 to '63; and Grant Feasel, a center from 1984 to '86.

The study included 202 former football players at the high school, college, semiprofessional and professional levels. Of those 202, 177 were found to have the brain disease chronic traumatic encephalopathy, or CTE, which can cause a wide range of neurocognitive problems. Among the 111 NFL players, CTE was discovered in all but one.

The study also noted that 93 percent of the 177 players with CTE had donated their brains to the study because they had shown cognitive trouble before their deaths.

Hawkins died July 28, 2015. He was 76 and had been found to have Lewy body dementia, which is considered the second most progressive form of dementia behind Alzheimer's disease.

Hawkins, a middle linebacker from North Carolina, was the 15th overall draft pick by the 1961 expansion Vikings. Running back Tommy Mason, the No. 1 overall pick that year, was the Vikings' top pick.

Hawkins played five seasons for the Vikings. He was the only rookie to lead them in tackles until Eric Kendricks matched that in 2015. Hawkins also is the only Viking to lead the team in tackles in his first four seasons. Kendricks has done it in each of his first two seasons.