Eagles linebacker Travis Long tore the anterior cruciate ligament in his left knee during Thursday night's preseason finale, NFL sources said.

Long, who tore the ACL in his right knee as a senior at Washington State, was expected to make the Eagles' 53-man roster. The team had been touting his development since spending last season on the practice squad. The outside linebacker was cross-training at inside and played there in the last two preseason games.

He recorded a fourth quarter sack of quarterback Tahj Boyd in the Jets game. A series later, he tore his ACL. His season is likely over.

The Eagles had no comment.

With Long likely headed to Injured Reserve, the Eagles will have an open roster spot. He was expected to be one of six outside linebackers to make the squad. Trent Cole, Connor Barwin, Brandon Graham, Marcus Smith and Bryan Braman were the others.

Long's injury had more affect on the inside linebacker corp and meant that Casey Matthews was slated to make the team and Emmanuel Acho was released, according to league sources. Matthews, now in his fourth season with the Eagles, will join DeMeco Ryans, Mychal Kendricks and Najee Goode at inside linebacker.

Long went undrafted last year mostly because of the torn ACL. The Eagles signed him as an undrafted rookie and kept him on their practice squad for all of his rookie season. He not only played both linebacker spots, but was on special teams and even played some two-gap defensive end in the nickel defense.