The 24-year-old linebacker who retired due to brain trauma concerns told Face the Nation on Sunday he will return 75% of his signing bonus.

Chris Borland said on Sunday's Face the Nation that he will pay back 75% of his $617,436 signing bonus the San Francisco 49ers.

CBS News

Borland signed a four-year rookie contract with the 49ers last year. The value of his lump-sum signing bonus was meant to cover playing time for the entire contract. For the three years he did not play, Borland said will pay back $436,077.

Host Bob Schieffer asked Borland about the NFL's statement, released after his retirement announcement, saying "football has never been safer. [...] We are seeing a growing culture of safety."

Borland replied, "Football is inherently dangerous, and that will never change. When I hit a fullback on a run play, talking about the culture of safety is irrelevant."

When asked about concussions, Borland said he is more concerned about cumulative sub-concussive brain trauma than the number of physician-diagnosed concussions, which he says have "20 different definitions."

Tony Avelar / AP

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