NEW ORLEANS -- The San Francisco 49ers' offense doesn't need any more challenges right about now.Yet, it may be dealt one. The team is awaiting word on the severity of a left knee injury suffered by standout guard Mike Iupati. He was carted off to the locker room during the 49ers' 23-20 loss at New Orleans on Sunday. He was seen leaving the locker room on crutches and with his knee in a brace.During the game, Iupati was replaced by Adam Snyder, who will play if Iupati has to miss significant time.