Brock Purdy questionable vs. Bengals due to concussion

The San Francisco 49ers listed quarterback Brock Purdy as questionable for their Week 8 matchup against the Cincinnati Bengals.

Purdy entered concussion protocol after playing in all of Monday's contest against the Minnesota Vikings.

The 23-year-old was a full participant in practice Friday and has one more protocol step to pass before he's cleared to play, head coach Kyle Shanahan said Friday, according to David Lombardi of The Athletic.

Shanahan added that Purdy will "definitely" start against the Bengals if he passes Saturday's protocol test.

Purdy reportedly started feeling concussion symptoms on the plane ride home from Minnesota last Sunday. It's unclear when he suffered the ailment.

The Iowa State product completed 21 passes for 272 yards with one touchdown and two interceptions against the Vikings. The 49ers lost the game, dropping their second straight contest and record to 5-2.

San Francisco also listed offensive Tackle Trent Williams (ankle) as questionable and ruled wide receiver Deebo Samuel (shoulder) out versus the Bengals.