49ers' Ian Williams performing well at nose tackle

Daily 49ers blog for NBC Bay Area website: Ian Williams wasn't the presumed starter at nose tackle going into 49ers training camp, but the way he's performing may lead to a big role in 2013. http://www.nbcbayarea.com/news/sports/Niners-Ian-Williams-Has-Been-Impressive-at-Nose-Tackle-217605431.html