FOXBOROUGH, Mass. - New England Patriots linebacker Jamie Collins didn't specify the kind of illness that sidelined him for four games. He just knows he's healthy and can be ready Sunday against the Philadelphia Eagles.

He was listed as questionable Friday against the Eagles after being a limited participant in practice since Wednesday.

"It feels really good to be back," Collins said.

The injury report also said that tight end Rob Gronkowski is out for the game with a knee injury. Receiver Julian Edelman also will miss the game with a foot injury.

Collins landed on the Patriots' practice report with an undisclosed illness after a 36-7 win against the Miami Dolphins on Oct. 29. He compared his symptoms to those of a stomach bug and said he lost a few pounds.

"I was just feeling bad, man," Collins said. "I don't want to talk about it. I don't want to talk about (those) memories."

Patriots coach Bill Belichick also was mum on Collins' illness. He said the situation can change on a daily basis with returning players.

"It's really a process and so we go by what we see," Belichick said. "Where a player is Wednesday, where he is Thursday, where he is Friday and even occasionally the Saturday changes are all just reflective of what the player's current condition is.

"And sometimes there is a straight line progression, but you don't know that until the end. You don't know it going along because you're not sure what's going to happen."

Collins had been off to a strong start, recording 51 tackles (29 solo) with 4.5 sacks and four forced fumbles through New England's first seven games.

"Nobody (wants) to sit out in this game — its fun," Collins said. "It was real hard."

Also Friday, the Patriots took part in a league-wide conference call on player health and safety. New England's Matthew Slater said NFL vice-president of officiating Dean Blandino has been passionate about it.

"I think that's something that needs to continue," Slater said. "You're never going to reach a point of satisfaction with that, and it's something that's ever evolving, ever changing."

NOTES: Slater and his wife recently celebrated the birth of their first child. ... Belichick shared his thoughts on Green Bay quarterback Aaron Rodgers' game-winning touchdown pass against Detroit on Thursday night. "I think it's not an overly strategic play," Belichick said. "You want to get the ball into the end zone and you want to get people around it."