SANTA CLARA, Calif. -- While star teammates such as quarterback Brock Purdy, tight end George Kittle, receivers Deebo Samuel Sr. and Brandon Aiyuk and defensive end Nick Bosa have missed games because of injury this season, San Francisco 49ers linebacker Fred Warner has been a stalwart.

But, as it turns out, that's not because Warner hasn't been dealing with his share of pain. Warner revealed for the first time Wednesday that he has been playing through a fractured bone in his ankle that he sustained in a Sept. 29 win against the New England Patriots.

That means when the Niners meet the Buffalo Bills on Sunday night, Warner will be playing his eighth consecutive game with the ankle injury.

"It's something I deal with every game," Warner said. "I get on that table before every game and get it shot up every single game just to be able to roll. But it's not an excuse. It's just what it is. That's the NFL. You're not going to be healthy. You've got to go out there, you've got to find ways to execute, to play at a high level and to win every single week."

Warner initially injured the ankle against the Patriots near the end of a first half in which he had already posted seven tackles and an interception for a touchdown on just 27 snaps. He did not play in the second half and expressed optimism after that game that he'd be OK.

In the following week, before the Week 5 matchup with the Arizona Cardinals, Warner was limited in practice but played in the game, finishing with 12 tackles, including one for loss. Warner has been a full participant in practice before every game since, though the injury has hindered him at times.

Still, Warner has 84 tackles, 1 sack, 4 forced fumbles and 2 interceptions on the season.

Asked whether the ankle would be able to heal before the end of the season, Warner acknowledged that was unlikely and he's going to have to continue playing through pain in order to reach the finish line.

"Any time you fracture a bone, if you just continue to play on it, the bone is usually not going to be able to heal itself," Warner said. "So, just got to continue to just fight through."

Warner and his teammates do expect a bit of an emotional boost Wednesday with linebacker Dre Greenlaw back on the field. Greenlaw has missed the first 11 games as he continues recovery from the torn left Achilles he sustained in the Super Bowl.

The 49ers officially opened Greenlaw's practice window Wednesday, giving the team and Greenlaw 21 days to prove he's ready to be activated from the physically unable to perform list to the 53-man roster.

"It'll be awesome just having him on the field," coach Kyle Shanahan said. "When Dre is around, whether it's on the field, in meeting rooms, he's 100% ball. Everyone loves him around here."

Meanwhile, the status for Purdy (right shoulder), Williams (left ankle) and Bosa (left hip/oblique) remains murky as the Niners begin preparation for Buffalo.

Purdy was a limited participant in Wednesday's practice, a sign of improvement from where he was Friday when the Niners ruled him out against the Green Bay Packers. 

Purdy threw one actual pass, a short screen during the third of four periods open to media Wednesday. Otherwise, he watched as the other quarterbacks (Brandon Allen, Joshua Dobbs and Tanner Mordecai) threw to receivers. Purdy also took part in the running game installation, handing the ball off to backs and attempting what appeared to be one shovel pass.

Williams was spotted in the locker room Wednesday with his left foot and ankle on a scooter and is not expected to participate in practice. The same is true for Bosa, though he spoke to the media and offered a positive update that he could potentially be back against the Bills.

Bosa said he's unlikely to do much in team drills during practice this week, but he could do some things Thursday and Friday.

"[I] made a good amount of progress for sure," Bosa said. "It's feeling a lot better. Still need to get better before I'm ready to go, so this week will be big, and I'll know a lot more in the next couple of days."

Running back Christian McCaffrey (rest day), guard Aaron Banks (concussion), defensive tackle Jordan Elliott (concussion), linebacker Demetrius Flannigan-Fowles (knee) and cornerback Deommodore Lenoir (knee) also missed Wednesday's practice. Guard Dominick Puni (shoulder), Greenlaw (Achilles) and defensive tackle Kevin Givens (groin) joined Purdy as limited participants.