SANTA CLARA -- Why did the 49ers defense fall apart so rapidly in the fourth quarter and overtime? The unit played 84 snaps on defense -- their second highest amount this season -- and was on the field for 41:55 of the game. Those who played every defensive snap: safeties Jaquiski Tartt and Antoine Bethea; cornerbacks Tramaine Brock and Jimmie Ward and defensive lineman DeForest Buckner, who ranks second behind New York Giants edge rusher Olivier Vernon in snaps played this season. Buckner has played 821 defensive snaps this season.
“I think they got worn down,” Chip Kelly said of his defense.