Shembo, a senior, started all 13 games for the Irish in 2012, tallying a career-high 51 tackles on the year. He leads all active Notre Dame players with 19 tackles for loss in his career, and he is tied with junior defensive end Stephon Tuitt for most sacks (14.0) among current Notre Dame players. Shembo was also named to the watch lists for the 2013 Lombardi Award and the 2013 Bednarik Award.
Fox and Calabrese are both fifth-year seniors, looking to anchor the Irish's strong defensive front seven.
Calabrese played in 12 games last season, starting five of those contests. He tallied 49 tackles and three tackles for loss.
Fox played in all 13 games in 2012, starting nine. He recorded 63 tackles on the season, two tackles for loss and one sack.
Former Irish linebacker Manti Te'o won the 2012 Butkus Award on the collegiate level. Te'o also won the high school Butkus Award in 2008. Notre Dame freshman linebacker Jaylon Smith won the high school version of the award last season.