Coach Mike Shanahan said Monday that Landry, who has missed the last four games, will be placed on injured reserve.
The hard-hitting Landry was making tackles in bunches in the Redskins' new defense during the early weeks of the season, but the sore tendon left him unable to practice for several weeks and forced him to play through pain.
The tendon was in danger of rupturing, so Landry's foot was placed in a walking boot about a month ago in hopes that he would heal in time to play again this year. After several attempts to get him back on the practice field, the staff has decided to end his season with the Redskins (5-8) out of the playoff race.
"I thought the first half of the season he'd be MVP with the way he was playing," Shanahan said. "Hopefully he can get well and get ready to go for next season."