BEREA, Ohio -- Browns running back Dion Lewis has been placed on season-ending injured reserve after undergoing surgery last week to repair a fractured fibula.

The move reduces the roster to 82, meaning seven more must be released by 4 p.m. Tuesday. Final cuts from 75 to 53 must be complete by Saturday at 6 p.m.

The loss of Lewis is a blow to the Browns, who had big plans for him as the backup to Trent Richardson

Lewis was an open-field threat who was acquired in a trade with the Eagles for second-year linebacker Emmanuel Acho in April.

Lewis, who averaged 4.5 yards on his 10 carries and caught seven passes for 37 yards and a touchdown, was injured against the Lions on Aug. 15. The Browns also lost Barkevious Mingo to a bruised lung and right guard Jason Pinkston to a high ankle sprain that game.

The loss of Lewis is compounded by Montario Hardesty's absence for at least the first two or three games of the season after arthroscopic knee surgery.

Brandon Jackson has moved into the No. 2 tailback spot. Chris Ogbonnaya, currently the first-team fullback, can double as a running back. The Browns also have running backs Miguel Maysonet and Jamaine Cook on the roster.