SANTA CLARA, Calif. – Barring any unforeseen circumstances between now and Sunday night’s game, San Francisco 49ers quarterback Brock Purdy will return against the Buffalo Bills.

According to coach Kyle Shanahan, Purdy is listed as questionable due to right shoulder soreness but has progressed enough this week to play barring a setback.

“A lot can still happen between now and then,” Shanahan said Friday. “But at the moment he is playing. He’s fine. Had a good day.”

Purdy did not play in last week’s 38-10 loss to the Green Bay Packers because of his shoulder problem. However, there were small signs of improvement earlier this week. He completed light throwing on Monday and had limited practice on Wednesday and Thursday. He was a full participant in Friday’s session with backup Brandon Allen, who wore a scout team jersey.

On Friday, Purdy spoke to Bay Area media for the first time since the Nov. 17 loss to the Seattle Seahawks. Purdy said it wasn’t one particular hit or moment that caused the shoulder discomfort, but rather an accumulation of things during the game.

Purdy had an MRI scan the Monday after the game that found no significant damage, but when he tried to throw at practice last Thursday, something felt off, prompting another MRI scan.

During this second exam, Purdy had some questions about whether there might be a long-term injury.

“Anytime you get an injury or something like that, you want to know what’s going on with your body and how long something might last or whether something is serious or not, whether you’re healthy or not,” Purdy said. “All of those things were definitely going through my mind. But I’m glad everything was clean in the MRI and I knew we had a plan to get ready for this week and I’m ready to go now.”

Purdy added that he felt completely like himself while throwing in practice on Thursday.

“The different things we did, like a throwing program, helped me feel good,” Purdy said. “Thanksgiving, I practiced there and felt good about it. And today I felt really good during training too.”

While Purdy’s return is a welcome sight for the 49ers, it doesn’t mean he will have his full supporting cast.

The 49ers ruled out left tackle Trent Williams (left ankle), defensive end Nick Bosa (left hip and oblique), cornerback Deommodore Lenoir (knee), guard Aaron Banks (concussion) and defensive tackle Jordan Elliott (concussion). The 49ers opened linebacker Dre Greenlaw’s practice window this week as he returned from a torn left Achilles, but he will not play against the Bills.

This is the second straight week the Niners will be without Bosa and Williams.

“We kind of understand what’s going on with them, it’s just a matter of how it heals,” Shanahan said. “And the boys, especially Trent, didn’t recover as much as we’d hoped. Hopefully they have a better chance next week. But in the end they never came back to training that week, so they weren’t that close in the end.”

Without Williams and Banks, the Niners will have a different look again on the left side of the line. Jaylon Moore, who filled in for Williams last week, will once again man the left tackle spot, with Ben Bartch and Spencer Burford among the options that could replace Banks.

This will be the second straight game Williams has missed due to injury. He was in the Niners locker room on Wednesday with a scooter holding up his left foot and ankle.

Lenoir was placed on the injury report this week after clashing knees with a Packers player in last week’s loss. He did not participate in any of the three practices this week before being ruled out.

The Niners will have at least one starter back against the Bills: Charvarius Ward, who hasn’t played since the Oct. 27 win over the Dallas Cowboys as he mourns the death of his 1-year-old daughter. Ward fully participated in every practice this week.

“We expect him to play,” Shanahan said. “He had a good week of training. … I’m excited to have him back out there.”