The Vikings won't know whether they're facing Bills starting quarterback Josh Allen or old friend Case Keenum until hours before Sunday's game. Buffalo listed Allen questionable to play, keeping the door open for him to play through an elbow injury that kept him to one limited practice on Friday.

The Bills are evaluating Allen "hour to hour," coach Sean McDermott told Buffalo reporters on Friday, "just looking at how he's going to progress through the day and as he goes through different tests medically."

The Bills held Allen out of practices Wednesday and Thursday.

Keenum 34, could make his first start for the Bills against one of his former teams. It'd be his 65th NFL start across seven different teams — his fourth since Minnesota let him leave following his 12 wins (including the Minneapolis Miracle playoff victory) as Vikings starter in 2017.

Keenum told Buffalo reporters this week he's "on the same page" with receiver Stefon Diggs as they could start their first game together since the playoff run five years ago. Keenum was asked whether there'd be extra enthusiasm to draw this start against the Vikings.

"Yes and no," Keenum said. "I've played a lot of my former teams before. That's what happens when you have a lot of former teams. You can only say those types of things when it's your first time doing it. I know how to treat those weeks, too."

Vikings head coach Kevin O'Connell is familiar with Keenum. O'Connell was Washington's offensive coordinator in 2019 when Keenum lost his first start against the Vikings.

"He played at a high level for us when I was coaching him," O'Connell said. "Just what he brings to a huddle from an experience standpoint, but then he knows exactly what he's looking at [in a defense]."

The Bills' top-ranked scoring defense will be without at least two starters in defensive end Gregory Rousseau (ankle) and safety Jordan Poyer (elbow), who were ruled out. Middle linebacker Tremaine Edmunds (groin/heel) is listed questionable and cornerback Kaiir Elam (ankle) is doubtful to play.

The Vikings defense will be without cornerback Cameron Dantzler (ankle) and defensive tackle Dalvin Tomlinson (calf). Dantzler's left ankle was supported by a walking boot on Friday. Rookie cornerback Akayleb Evans is expected to get his first NFL start while defensive lineman James Lynch started last week for Tomlinson.

Center Garrett Bradbury (ankle) is expected to play.

Preparing for cold and crowd

O'Connell has had the Vikings practice outside Thursday and with the doors open to the indoor fieldhouse on Friday, when the temperature was 29 degrees, to prepare for what's forecasted to be a windy 40 degrees on Sunday in Orchard Park, N.Y. Coaches also had the equipment crew roll out giant speakers for crowd noise to mimic a more ambitious road atmosphere than the lackluster, bipartisan effort in Washington.

"Their crowd definitely gets loud," receiver Justin Jefferson said. "Going to Buffalo for the first time, nobody really knows exactly what the weather is going to be like, but I'm excited to be in that atmosphere, to be in that environment, playing in big games and playing a pretty good defense as well. Just like we've talked throughout the whole year, I live for those types of games."

Party refreshments

Regarding quarterback Kirk Cousins' post-road win alter ego, "Kirko Chains," offensive coordinator Wes Phillips said he misses "the time when that moment on the plane was for us" and not a public talking point. Phillips, 43, said flights back from games are one of his favorite parts about working in the NFL.

"I've never been around a quarterback taking his shirt off on the plane," Phillips said. "But they're having fun. Kirk's got kind of a refreshing genuineness about him. He knows who he is, he doesn't try to be anything else, and I think guys feel that and gravitate toward that."

'I'll be back'

Tight end Irv Smith Jr. was putting the walking boot back on his sprained left ankle Friday afternoon when he said, "I'll be back" this season. Smith, who is scheduled to become a free agent after this season, said he did not require surgery after seeking a second opinion on the injury suffered Oct. 30 against the Cardinals.

The Raiders signed tight end Jacob Hollister off the Vikings practice squad on Friday. Tight end Ben Ellefson, a Hawley, Minn., native, is an option on the practice squad after he was cleared to return from injured reserve this week.