The San Francisco 49ers are still favored to end their two-game losing streak, but their odds did take a hit with the news that quarterback Brock Purdy is in the concussion protocol.

Coach Kyle Shanahan revealed that Purdy began experiencing symptoms on the flight back from San Francisco’s loss at Minnesota on Monday night that dropped the 49ers to 4-2. He could clear the league’s protocol in time to face Cincinnati (3-3) on Sunday, but Purdy’s status will be in limbo possibly until game day.

DraftKings reported that the 49ers went from 5.5-point favorites to 4.0-point favorites following the news of Purdy’s injury, while their moneyline shifted from -230 to -192. Meanwhile, the Bengals’ moneyline moved from +190 to +160, and the Over/Under shifted slightly from 45 to 45.5 points.

Backup quarterback Sam Darnold will take first-team reps, though Purdy is allowed to participate in some portions of Wednesday’s walkthrough, Shanahan said.

“He does have enough time,” Shanahan said of Purdy’s chances of playing Sunday. “Just has to go through the process.”

Purdy played the entire game against the Vikings, and Shanahan said it’s unclear when exactly Purdy might have suffered the injury.

Purdy threw for 272 yards with a touchdown and two interceptions in the loss. He is completing 67.9 percent of his passes for 1,668 yards, 11 touchdowns and three interceptions on the season.

The 49ers signed Darnold, the 2018 draft’s No. 3 overall pick, as a free agent in March. He beat out Trey Lance for the backup position during training camp, with Lance ultimately traded to Dallas.

Darnold has appeared in four games this season in mop-up duty. He’s 21-34 in his career as a starter.

Journeyman Brandon Allen is the 49ers’ third-string quarterback.

–Field Level Media