"He does have enough time [to clear the protocol before Sunday]," head coach Kyle Shanahan said. "He's just got to go through the process."
Shanahan noted that Purdy is feeling better than he did earlier in the week, which bodes well for the second-year quarterback and the 49ers.
For now, the 49ers must ready themselves for the possibility of Purdy being unavailable. That means preparing backup quarterback Sam Darnold for what could be his first start with the team since joining as a free agent back in March.
"I have as much confidence as Sam as I could have with someone that I haven't gone into a real NFL game with," Shanahan said. "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.
"He doesn't get many reps, as no backups do, but he does well on the scout team. 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."
Darnold brings with him a wealth of NFL experience, having 55 starts under his belt. He played relatively well in six games with the Carolina Panthers last season, boasting a 4-2 record while passing for 1,143 yards, seven touchdowns, and three interceptions.
At 26 years old, Darnold is entering his sixth NFL season. He owned a 17-32 record as a starter before last season.