Brown was carted off the practice field with a left knee injury Monday, and the news was made official Tuesday morning -- he's out for the year with an ACL tear. Surgery to repair the injury is scheduled for Wednesday.
It's a huge blow for the Duke defense, but equally devastating for Brown, a redshirt senior who will now be undergoing ACL surgery for the third time in his career.
Brown's emergence last season closely paralleled Duke's run to a division title. During a crucial three-game stretch when the Blue Devils upset Virginia Tech on the road, escaped NC State with a dominant fourth quarter and downed Miami, Brown racked up 41 total tackles, including four for a loss, and forced two fumbles.
With the loss of Brown, Duke's options at middle linebacker are a bit thin. Junior Deion Williams projects as the likely replacement. Williams has just one career start, coming last season against Navy. For the season, he recorded 17 tackles.
While Duke's defense made its share of big plays last season, the unit struggled with consistency. The Blue Devils finished 12th in the ACC in total defense, allowing 418 yards per game, and their 4.93 tackles for loss per game were the sixth fewest among all Power Five conference teams. Brown was responsible for 11 of Duke's 69 tackles behind the line of scrimmage, tops among returning defenders, and he was one of the key leaders in the locker room.
Brown tore his right ACL twice, including an injury that cost him all of 2012. He returned last season to help lead Duke to a 10-win campaign and a berth in the ACC championship game. His 114 tackles ranked third in the ACC, behind teammates David Helton and Jeremy Cash. Brown was named to the All-ACC team at year's end and was again a preseason selection this season.
Brown's brother, Kyler, is a reserve defensive end for Duke after moving from linebacker during the spring.
Because of his previous knee injuries, Kelby Brown could petition the NCAA for a sixth year of eligibility and return in 2015.