In this Nov. 5 file photo, Stanford running back Christian McCaffrey smiles after Stanford defeated Oregon State 26-15. McCaffrey is done playing college football. Stanford&amp;#x2019;s star running back announced on Twitter on Monday, Dec. 19, 2016, that he will not play in the Sun Bowl game against North Carolina on Dec. 30 in El Paso, Texas. Photo: ASSOCIATED PRESS FILE PHOTO

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