After a season that failed to live up to expectations and a lackluster final attempt at redemption in the Sun Bowl, the last thing the USC football team needs is more bad news.But the lack of depth at the cornerback position is sure to pose yet another problem.Saying goodbye · USC will be hard-pressed to replace junior cornerback Nickell Robey’s leadership and All-Pac-12 production. – Chris Pham | Daily TrojanJunior cornerback Nickell Robey officially confirmed that he will declare for the NFL draft with one season of eligibility remaining.Robey unofficially announced that he would enter the draft two weeks ago on Facebook and briefly reconsidered in the aftermath of USC’s bowl loss, but finally informed coach Lane Kiffin of his decision on Sunday.The Florida native becomes the second player to declare for the draft early; wide receiver Robert Woods announced his decision to enter the NFL draft shortly after USC’s loss to Georgia Tech in the Sun Bowl.The vacant slot left by the three-year starter won’t be easy to fill. In his career at USC, Robey demonstrated toughness and speed, earning multiple All-Pac-12 honors and winning the John McKay Award for Most Competitive Underclassman in 2011. In his 38 career starts, he recorded 163 tackles and seven interceptions, three of which were returned for touchdowns.With his early departure, the Trojans lack proven players at the position.Redshirt junior Torin Harris struggled in his appearances this season, and after being declared academically ineligible prior to the Sun Bowl, he remains a question mark heading into next year.Other options currently on the roster, such as redshirt sophomore Anthony Brown and redshirt sophomore Josh Shaw, a converted safety, lack the experience and accolades that Robey will take with him to the next level.On the recruiting front, Sebastian LaRue, a versatile recruit who can play multiple positions including cornerback, decommitted from the USC program. Incoming freshman Jalen Ramsey and Chris Hawkens, however, are still committed and are expected to compete right away for playing time.Another issue still looming on the defensive side is when head coach Lane Kiffin will name his defensive coordinator. Former defensive coordinator Monte Kiffin, who was let go prior to the team’s Sun Bowl loss in December, was recently hired by the Dallas Cowboys to the same position.