Manuel was a full participant in Wednesday's practice, splitting snaps with Thad Lewis, who also is returning from injury.
"EJ has taken more reps than Thad right now," coach Doug Marrone said Wednesday. "I just want to make sure I feel comfortable before I come out with a statement. But right now, we're working with both of those guys."
Marrone said both players showed "a little bit of rust" in Wednesday's practice.
But Marrone also said that Bills CEO Russ Brandon's take on Manuel's health earlier Wednesday -- that he should be ready to play Sunday -- is on point.
"It's a very fair assessment," Marrone said. "I just want to make sure in my mind, once the plan is in and he's doing all the things that we need to do to win, then we can say, 'Hey, go ahead and do it.'"
Manuel wasn't hesitant Wednesday about his ability to play.
"I definitely feel like I can go," Manuel said. "It's still up to Coach Marrone, as far as what we want to do as a team, but I definitely feel confident going into Sunday."