49ers LB Smith leaves game with injury

San Francisco 49ers linebacker Aldon Smith left Friday's preseason opener against the Minnesota Vikings with a leg injury.

Smith was carted off the field to the locker room after the second play of the Vikings second drive of the game, CSN Bay Area reported. The team did not give any information about the injury.

In his second year, Smith is coming off a rookie season in which he collected 14 sacks. He has been moved to a starting outside linebacker spot after being a third-down pass-rushing specialist last year.