Second-year defensive end Alex Buzbee suffered a ruptured Achilles injury during Sunday afternoon's training camp practice.
He is expected to undergo season-ending surgery on Monday, head coach Jim Zorn said.
Buzbee joins Phillip Daniels as defensive linemen to be lost for the season on training camp's first day.
Buzbee, 6-3 and 246 pounds, spent most of last season on the Redskins' practice squad. He was promoted to the active roster on Dec. 12, 2007, but was inactive for the team's final three games.
Buzbee played his college ball at Georgetown, where he totaled 27.5 sacks in four seasons.