Williams, 23, was placed on injured reserve Wednesday after clearing the league's concussion protocol.
The concussion occurred late in the third quarter of last Sunday's stunning upset of the Los Angeles Rams, which likely cost the Jets the No. 1 overall pick in the 2021 NFL draft. Williams, caught on camera as he walked to the locker room for an evaluation, was seen vomiting on the sideline.
Williams, drafted third overall in 2019, was one of the few bright spots this season for the Jets (1-13). After a lackluster rookie year, he became a disruptive presence on the defensive line. He leads the team in sacks (seven) and quarterback hits (14) and ranks among the league leaders in the major run-stopping metrics, according to NFL Next Gen Stats.
"On Sunday, you saw what kind of impact he had -- a ton of TFLs [tackles for loss], was in their backfield and created pressure," Gase said.
Gase said Williams "kind of disappeared" in some games, "but it didn't happen a lot this year. Last year, I felt like there would be a couple of games in a row where you didn't really feel him. But this year, I felt like the high majority of the game you felt him. If you were on the other team, you felt him whether you were playing quarterback or in the running game."
The Jets also placed inside linebacker Harvey Langi (neck) on IR. Between injuries, in-season trades and one opt-out, the Jets are down seven defensive starters from the unit that was projected at the start of training camp.