Article Photos: Oklahoma football: Sooners' defensive backfield lacks depth 25/57

Trevor Knight chases a fumble through the legs of Chuka Ndulue (98) during the annual Spring Football Game at Gaylord Family-Oklahoma Memorial Stadium in Norman, Okla., on Saturday, April 13, 2013. The fumble was picked up by Frank Shannon (20) and carried in for a score.  Photo by Steve Sisney, The Oklahoman