Buffalo Bills quarterback Josh Allen will be active Sunday despite his ulnar collateral ligament injury and the belief is he will start against the Minnesota Vikings, sources told ESPN on Saturday.

Bills officials, however, have been tight-lipped all week and have declined to reveal who is starting and want to keep it secret until after Sunday's NFL actives/inactives list is released at 11:30 a.m. ET. Bills officials spent intensive time this past week leaning on and listening to their doctors and other arm specialists, and the team was reassured that Allen is not at any added risk to make the injury worse if he plays Sunday against the Vikings, sources said.

With this in mind, the sources say the belief is that Allen will start Sunday, but the team has declined to confirm any final decisions and insists it is taking it "minute by minute" and doesn't want to give the Vikings any competitive advantage by naming a starting quarterback.

Allen was limited in Friday's practice, when he was seen with a practice jersey on and no sleeve on his right arm. If he starts, he will have participated in only one day of practice after sitting out Wednesday and Thursday.

"We are literally in an hour-to-hour situation here just looking at how he's going to progress through the day," coach Sean McDermott said Friday. "And as he goes through these different tests, medically, making sure that he's able to check the boxes in a progression to where we can see if we can proceed through the course of the day here."

Allen is dealing with a right elbow injury to the ulnar collateral ligament and related nerves, sources told ESPN's Chris Mortensen earlier in the week. It happened on the last drive of Sunday's loss to the New York Jets. He has not missed a game since 2018, when he missed four games with a UCL injury in his right elbow.

ESPN's Alaina Getzenberg contributed to this report.