Oklahoma's Buddy Hield (right) and Denzel Valentine of Michigan State played in Friday's East Regional Semifinal of the 2015 NCAA tournament in Syracuse. If you've got money riding on this year's NCAA tournament, you might want to hear about what happened to John Bovary's football pool. Maddie Meyer/Getty Images hide caption

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San Francisco 49ers linebacker Chris Borland, center, during an NFL football game in Santa Clara, Calif. Borland announced that he will retire after just one season to protect himself from brain injuries. Marcio Jose Sanchez/AP hide caption

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Philadelphia Eagles Chuck Bednarik (60) is victorious in an iconic 1960 photograph after making a sack vs. New York Giants Frank Gifford (16). Bednarik died on Saturday. He was 89. John G. Zimmerman/Sports Illustrated/Getty Images hide caption

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Malcolm Butler (right) of the New England Patriots intercepts a pass intended for Ricardo Lockette of the Seattle Seahawks late in the fourth quarter of Super Bowl XLIX on Sunday. Timothy A. Clary/AFP/Getty Images hide caption

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Football rules, uniforms, helmets and protective gear have changed a lot over the years. Keystone-France/Gamma-Keystone via Getty Images hide caption

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Bill Parcells has been coach to the Dallas Cowboys, the New York Giants, the New England Patriots and the New York Jets. Robert B. Stanton/Getty Images hide caption

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Rafael Nadal (right) shakes hands with Tim Smyczek after winning a match at the Australian Open on Jan. 21. Rob Griffith/AP hide caption

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High school athlete Graham Hill, number 50, suffered a concussion in 2013 while playing football at Trinity Christian Academy in Addison, Texas. Courtesy of Jeffrey McWhorter hide caption

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New England Patriots head coach Bill Belichick speaks during an NFL football news conference at Gillette Stadium, on Saturday in Foxborough, Mass. Belichick defended the team against allegations they had cheated by using underinflated footballs in a championship game. Steven Senne/AP hide caption

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New England Patriots head coach Bill Belichick, seen here on Jan. 18, says he "had no knowledge" about the controversy over deflated footballs "until Monday morning." Elise Amendola/AP hide caption

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Panelist Nahshon Ellerbe, a star running back at Trinity Christian Academy in Addison, Texas, warms up before a game against Midland Christian. Jeffrey McWhorter/Trinity Christian Academy hide caption

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The Army-Navy game on Dec. 7, 1963, was the first televised sports game featuring instant replay. Its inventor, Tony Verna, died Sunday at 81. AP hide caption

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Boyd Dowler of the Green Bay Packers grabs a Bart Starr touchdown pass in the NFL championship game on Dec. 31, 1967. The "Ice Bowl," played in frigid temperatures, was won by the Packers 21-17. AP hide caption

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The Yale football team in an undated photo. Commentator Frank Deford finds it curious that a sport as brutal as football became popular among the academic elite. AP hide caption

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