University of Arkansas junior running back Knile Davis sustained an injury to his left ankle during practice Thursday evening and is expected to miss the 2011 season. "I am extremely disappointed for Knile," UA head coach Bobby Petrino said. "He is a captain who was incredibly focused on the upcoming year. His leadership throughout the offseason was significant in the development of this team. Our athletic trainers and medical staff are the best in the country, and Knile's mental toughness will be an asset to him during the recovery process. I am fully confident in the mindset of our running back group and their ability to perform."