San Francisco 49ers quarterback Alex Smith threw a 14-yard touchdown pass in the second quarter of Sunday's 24-24 tie against the Rams while playing with blurred vision before coming out with a concussion.
Coach Jim Harbaugh said Monday that Smith connected with Michael Crabtree six plays after he began experiencing blurred vision on a 1-yard keeper early in the second quarter. Six plays earlier, he had taken a vicious hit from St. Louis linebacker Jo-Lonn Dunbar.
Smith scrambled to his left and started to slide before turning when Dunbar got him in the back of the neck with 1:10 left in the first quarter. He briefly grabbed his face mask and grimaced but stayed in the game.
''He said he had the blurred vision after the quarterback sneak,'' Harbaugh said. ''There's no telling. Did that earlier hit contribute? I don't know. I don't know Alex knows for sure, either.''
Second-year backup Colin Kaepernick entered for the next offensive series after a hurried warm up.