The Eagles moved to replace Jackson by agreeing to terms with veteran defensive tackle Akeem Spence on Tuesday evening. Tight end Alex Ellis was waived in a corresponding move.
"Yeah, we'll probably be without him for a while," defensive coordinator Jim Schwartz said Tuesday. "Malik is an important part of what we do and we will certainly miss him, but we've got plenty of guys who can step up and play, and that's nothing new in the NFL."
According to the NFL Network, Jackson will have Lisfranc surgery next week, a procedure that is expected to sideline him for the season.
Jackson was injured late in Philadelphia's 32-27 win while rushing the passer. He left on a cart and exited the stadium in a walking boot.
The Eagles signed Jackson to a three-year, $30 million deal this offseason. Pairing Jackson with Fletcher Cox, Philadelphia was slated to have one of the top defensive tackle duos in the NFL. Tim Jernigan is expected to step into a starting role while Jackson is out.
Jackson posted 32.5 sacks in seven seasons with the Denver Broncos and Jacksonville Jaguars. He earned a Pro Bowl bid after racking up eight sacks for Jacksonville in 2017. His signing was expected to partially offset the departures of Chris Long and Michael Bennett, two of the top pass-rushers for Philadelphia in 2017.
Jackson's injury heightens the chances that the Eagles will deploy their "race car package" on passing downs, featuring three defensive ends around Cox, which could mean an increased role for players such as Vinny Curry.
"We'll get him healthy and get him back," Schwartz said. "And if I know Malik, he'll do a good job staying engaged while he's rehabbing. I've been impressed with him not just as a player but as a professional."
Spence, 27, started 16 games for the Miami Dolphins last season. He has 10.5 sacks in 88 games over six seasons.