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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Syracuse coach Jim Boeheim, right, speaks with an official during the first half of an NCAA college basketball game against Duke in Durham, N.C., on Feb. 28 Gerry Broome/AP hide caption

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New York Yankee Alex Rodriguez watches from the dugout during an intrasquad game at a spring training baseball workout Monday in Tampa, Fla. Lynne Sladky/AP hide caption

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Kurt Busch drives during the NASCAR Sprint Cup Series auto race in Fort Worth, Texas, on Nov. 2, 2014. Busch was recently suspended indefinitely amid domestic violence accusations. Larry Papke/AP hide caption

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UNC Tar Heels head basketball coach Dean Smith gives instructions during a 1997 playoff game against the Colorado Buffaloes. Smith died Saturday. He was 83. Doug Pensinger/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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The Atlanta Hawks' Mike Scott scores over the Detroit Pistons' Greg Monroe in a game Monday. The Hawks are currently leading the NBA's Eastern Conference. Dave Tulis/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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