Nebraska junior Charles Jackson, expected to be the Huskers' main nickelback this season, will miss the 2014 campaign with a knee injury.
Coach Bo Pelini announced Thursday night that Jackson (5-foot-11, 180 pounds), one of the best athletes on the team, needs surgery to repair a knee injury.
Jackson played sparingly as a backup corner and safety in his first two seasons but was a special-teams standout. He had a strong spring, though, and was in line to replace Ciante Evans -- who had four interceptions and six pass breakups last season -- as the top nickelback. The Huskers use a lot of sets requiring five defensive backs, so his loss is a setback to the defense as a whole.
The secondary was a concern before Jackson's injury, as just one fulltime starter -- strong safety Corey Cooper -- returns from last season. Cornerback is an especially thin position even though coaches expect a solid season from senior Josh Mitchell, who was a part-time starter at corner last season.
With Jackson's loss, Nebraska's top two nickelbacks have not played a down of college football. Junior college transfer Byerson Cockrell, who enrolled in time for spring ball, now is the top candidate, while true freshman Joshua Kalu also is in the mix. Cockrell was considered one of the nation's top 10 JC safeties in the 2014 recruiting class.