Brock Purdy's participation in the San Francisco 49ers' Week 8 game with the Cincinnati Bengals looked in serious doubt after he was placed in the concussion protocol.

However, the Niners quarterback appears set to overcome the odds and lead the San Francisco offense in the final game before the bye.

Purdy practiced for the second straight day on Friday, indicating he is on course to pass the protocol on Saturday.

That would remove the possibility of backup Sam Darnold starting his first game for the Niners.

Head coach Kyle Shanahan said of Purdy's week of practice in his press conference: "Nothing's been different. He could only do walkthrough the first day, so he missed a couple periods with that, then we had helmets on versus the defense."

Purdy appeared to suffer the concussion on a fourth-quarter QB sneak during the Niners' 22-17 loss to the Minnesota Vikings on Monday. He endured a helmet to helmet collision with Vikings linebacker Jordan Hicks. His next throw after that hit was an interception.

He subsequently threw another interception on the final drive when the Niners had a chance to complete a comeback.

Prior to those picks, Purdy had produced another assured performance. He finished the game 21 of 30 for 272 yards and a touchdown along with his two interceptions.

While Purdy's apparent speedy recovery will be a huge boost to the 49ers, they may again be without All-Pro left tackle Trent Williams, who missed Monday's loss with an ankle injury and was not seen at the start of Friday's practice for the section open to the media.

San Francisco 49ers-Cincinnati Bengals broadcast map: Will you be able to watch on TV?

Most of the country will get the game.