He suffered the season-ending injury in the first quarter of Washington's 23-3 loss to Baltimore at M&T Bank Stadium.
Murphy will miss the 2017 season and deprive the Redskins of a key pass rusher.
The Redskins are already thin at outside linebacker, where Ryan Kerrigan and Preston Smith are now listed atop the team's depth chart.
Trent Murphy was supposed to miss the first four games of the season, now it looks like he'll miss all of the 2017 campaign.
Icardi, lettera all'Argentina: "Daro' tutto per te"
Un chiaro riferimento al fatto che, per gli argentini , ora Icardi è diventato un vero e proprio punto di riferimento. Ecco quanto si legge: "Il Pipita non è stato convocato".
Murphy left the game after this play and was seen on crutches in the locker room. In his first three seasons in Washington, Murphy appeared in 47 regular-season games with 22 starts, registering 112 tackles along with 15 sacks, six forced fumbles and four fumbles recovered. Washington's outside linebacker corps is now thin, at least currently.
Murphy, a free agent after the season, was coming off a career-best nine sacks and was playing well in the preseason opener before the injury. The Redskins have stalwart Ryan Kerrigan as a starter but are presently without a healthy Preston Smith or Junior Galette.
Now, he'll be out for the full season.