FOXBORO — Patriots left tackle Trent Brown returned to practice Thursday after sitting out Wednesday with an illness, while veteran receiver JuJu Smith-Schuster was newly absent.

Smith-Schuster was one of four missing players, along with safeties Jabrill Peppers (hamstring) and Jalen Mills (concussion) and rookie receiver Kayshon Boutte. It’s unknown why Boutte was absent. Smith-Schuster has missed the team’s last two games with an ankle injury.

If neither receiver can play Sunday, the Patriots will be down to DeVante Parker, DeMario Douglas, Jalen Reagor and Tyquan Thornton in Buffalo.

The Patriots listed three players as non-participants and another nine as limited on their initial injury report Wednesday. They will release their next report sometime Thursday evening.