Could there be a twist in the San Francisco 49ers' Week 8 quarterback drama? The smart money says no, but the Niners can afford to be at least somewhat encouraged after Brock Purdy practiced in a limited capacity on Thursday as he works his way through the concussion protocol.

Despite Purdy's presence on the field as the Niners prepare to face the Cincinnati Bengals on Sunday, the likelihood is that Sam Darnold will be the San Francisco quarterback tasked with helping Kyle Shanahan's team end a two-game losing streak.

Darnold's task will be much easier if he has All-Pro left tackle Trent Williams on the offensive line, and it is still up in the air whether that will be the case.

49ers Injury Report

Injury report observations

Williams is the major story aside from Purdy given the struggles of the 49er offensive line in Monday's loss to the Minnesota Vikings.

The Vikings dominated the line of scrimmage, their six-man front throttling San Francisco's run game, while pass protection against Minnesota's ultra-aggressive pass rush proved a major issue.

Williams' stand-in Jaylon Moore was arguably the least culpable of any play on the O-Line, but the 49ers would obviously greatly benefit from having the 10-time Pro Bowler back in the lineup to provide a fortifying presence against Trey Hendrickson and Co. and improve Darnold's comfort level in his prospective first start for the Niners.

Kyle Shanahan had on Wednesday expressed optimism Williams would practice on Thursday. That did not happen, but Williams was seen working on a side field.

The 49ers will give a player of his pedigree and experience every chance to play, but the prospect of him being out there for a fascinating matchup will look an unlikely one if he does not practice on Friday.

What can 49ers expect from Sam Darnold vs Bengals in Week 8?

It’s going to be fascinating to watch.