49ers' Kyle Shanahan talks Sam Darnold confidence amid Brock Purdy uncertainty

San Francisco 49ers head coach Kyle Shanahan insisted Wednesday he's confident backup quarterback Sam Darnold can deliver a win if starter Brock Purdy can't play in this coming Sunday's home game against the 3-3 Cincinnati Bengals. 

"I have as much confidence in Sam as I could have with someone that I haven't gone into a real NFL game with," Shanahan explained, per David Bonilla of 49ers WebZone. "He was great in the offseason, he's been great here in these seven weeks so far and he's always ready to go. He's great in the meetings and stuff."

The 49ers signed Darnold early in free agency and presumably leaked as far back as the spring that he was trending toward leapfrogging 2021 first-round draft pick Trey Lance on the depth chart. San Francisco then left no doubt about the situation when the club traded Lance to the Dallas Cowboys in late August. 

Shanahan confirmed Wednesday that Purdy entered the concussion protocol coming off the team's "Monday Night Football" loss at the Minnesota Vikings that dropped the 49ers to 5-2 on the season. The coach added that Purdy technically "does have enough time" to clear the protocol by Sunday's Cincinnati game, but history suggests the 23-year-old will remain sidelined through San Francisco's Week 9 bye. 

According to Eric Branch of the San Francisco Chronicle (h/t MSN), Darnold completed 22-of-33 pass attempts for 282 yards with two touchdowns and an interception during his first preseason with the 49ers. Darnold thus far has thrown a single regular-season pass since Week 1. 

"He doesn't get many reps, as no backups do, but he does well on the scout team," Shanahan said about Darnold. "He's always good in the meetings. We've got mainly walkthrough today, so Brock's allowed to do some of the walkthrough. We've got a couple of periods that aren't, so Sam will get those periods."

While the spread for this Sunday's matchup changed after Shanahan shared the Purdy update, OddsChecker showed late Wednesday afternoon that the 49ers were listed as 3.5-point favorites against the Bengals.