Lee's production tough to replace

Cowboys linebacker Sean Lee was taken off the field with a left knee injury during Cowboys’ organized team activities Tuesday. The Cowboys fear Lee tore his ACL, an injury that would take away one of Dallas’ most productive defenders.

Since his 2010 rookie season, Lee is the Cowboys’ leader in tackles (281) and interceptions (11). Lee’s 11 interceptions over the last four seasons lead all linebackers.

Most Interceptions by LB Since 2010

Lee is one of the league’s top tacklers. He averaged 9.2 tackles per game in the last two seasons, fifth among players with at least 10 games played. Lee was 3rd in the league in tackles last year before injuring his hamstring in Week 10 against the Saints.

During Lee’s career, the Cowboys allowed 4.1 yards per rush with Lee on the field, an average that would have tied for 12th-best in the league over that span. Without Lee, Dallas’ 4.7 yards per rush allowed would rank 31st in the league over that span.

The strong start to Lee’s career prompted Dallas to sign him to a six-year contract extension last August. Productivity has never been a problem for Lee, but durability is another story.

Lee missed the entire 2008 season at Penn State with a torn right ACL during a non-contact drill, and partially tore his left ACL in 2009. In 2012 and 2013, Lee missed 15 total games with neck, hamstring and toe injuries. Should Lee’s injury be serious, the 2014 season will be the third-straight in which Lee has missed at least five games.

It could be a critical loss for Dallas, a team that allowed 6,645 yards last season, third-most by a team in NFL history. Dallas has finished 8-8 in 3 straight seasons and missed the playoffs in 4 straight seasons, the Cowboys’ longest streak under Jerry Jones.

Cowboys Defense Last Season

Lee’s injury leaves Bruce Carter (96 tackles) as the only linebacker on the Cowboys roster who made at least 25 tackles last year. Ernie Sims (41 tackles with the Cowboys last year) is still an available free agent, and Dallas drafted Iowa linebacker Anthony Hitchens in the fourth round.

Lee is the latest notable player injured during the league’s organized team activity period. He joined Hakeem Nicks (foot in 2012, Michael Crabtree (Achilles in 2013) and Melvin Ingram (ACL in 2013) as players with serious injuries during organized team activities in the last three seasons.

Lee is also the latest NFL player with a serious knee injury. There were 125 players placed on injured reserve with knee injuries last year, up from 121 in 2012 and 93 in 2011.