League sources told NFL Media that Jackson suffered a Lisfranc injury late in Sunday's game against the Washington Redskins. He is expected to be out for the remainder of the season due to the injury.
"Malik's an important part of what we do and we'll certainly miss him when he's [not] on the field, but we got plenty of guys that can step up and play and that's nothing new in the NFL," Eagles defensive coordinator Jim Schwartz said. "Doesn't change our task from game-to-game and it doesn't change our task over the course of the year.
"We'll get him healthy and get him back. If I know Malik, he'll do a good job staying engaged while he's rehabbing. I've been really impressed with him as a professional, not just as a player but as a professional."
Philadelphia agreed to terms with defensive lineman Akeem Spence to fill Jackson's roster spot, the team announced Tuesday.