SANTA CLARA, Calif. (AP) — 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.