The Washington Redskins return to training camp Saturday for one practice that starts at 1:30 p.m.
Murphy already was going to miss the first four games of the season after being suspended for violating the NFL's policy on performance enhancing drugs.
This was the final year of Murphy's rookie contract, meaning he will become an unrestricted free agent at the end of the season.
Murphy fell and twisted his left knee awkwardly in the first quarter of the team's preseason game against the Ravens Thursday night. Washington's outside linebacker corps is now thin, at least currently.
It's an unfortunate blow for Murphy, who is coming off the best season of his career, during which he recorded nine sacks and 55 quarterback pressures (sacks plus hits plus hurries). Murphy was playing behind Ryan Kerrigan and Preston Smith. The latter has missed two full seasons and still hasn't played for the Redskins despite signing in D.C.in 2015. He figures to factor into the pass-rushing equation more prominently after this unfortunate development.