Brown recorded 114 tackles, 11 tackles for loss and two interceptions last season.
This is Brown's third major knee injury since he arrived at Duke as a three-star recruit in 2010. Brown tore the ACL and MCL in his right knee in November 2010 and sat out the 2012 season after tearing his ACL in the same knee in February of that year.
Brown, who has been described as the vocal leader and "heart" of Duke's defense, was selected to the 2014 preseason All-ACC team. Duke coach David Cutcliffe said several players would compete to replace Brown, according to the Raleigh News & Observer.
Duke went 10-4 and won the ACC Coastal Division in 2013. The Blue Devils open the 2014 season Aug. 30 against Elon.
- Chris Johnson