Kerrigan suffered a calf injury in the third quarter of Sunday's loss at Green Bay and did not return. Kerrigan had never missed a game in his nine-year career until sitting out a Week 13 win at Carolina because of a concussion. That snapped a streak of 139 consecutive games played.
The four-time Pro Bowler started slowly, with only two sacks in his first nine games, but he had 3.5 in his last three. Kerrigan had finished with less than 11 sacks just once in the past five years. His previous low was 7.5 sacks in his rookie season.
Kerrigan is second on the Redskins' all-time sack list with 90, trailing Dexter Manley by one. The sack did not become an official statistic until 1982; Manley began playing in 1981.
"He's a consummate pro in every respect," Redskins interim coach Bill Callahan said. "I know that he didn't want to finish this year, this season, in this fashion. It's in the best interests of his health to go this route."
Kerrigan has one year left on his contract, but this will be an interesting offseason for Washington. The Redskins could undergo changes in the front office and will likely have a new coaching staff.
In the immediate future, Kerrigan will be replaced by third-year linebacker Ryan Anderson, who will be opposite rookie Montez Sweat. Against Carolina, Sweat spent more time at Kerrigan's left outside spot and recorded 1.5 sacks.
The Redskins signed tight end Caleb Wilson to take his roster spot. Wilson was the last pick in the 2019 draft. He had been on Arizona's practice squad.