It's another blow to the Eagles (3-4), who have been hit hard by injuries after their Super Bowl season.
Barnett, a second-year player out of Tennessee, moved into a starting role this year after Vinny Curry left for the Tampa Bay Buccaneers in free agency. He posted 2.5 sacks and 14 quarterback hurries over six games.
Michael Bennett is likely to step into a larger role in Barnett's absence. The 10-year vet has been coming on of late, posting three sacks over the past four games. Rookie Josh Sweat could move into the rotation as well.
The Eagles' defense is down several players. Safety Rodney McLeod (MCL) is on injured reserve and defensive tackle Tim Jernigan has yet to play this year after surgery to repair a herniated disk. Cornerback Sidney Jones (hamstring) and defensive tackle Haloti Ngata (calf) have also missed time of late.
The depleted Eagles play against the Jacksonville Jaguars in London Sunday.