CINCINNATI -- Deebo Samuel will play, but is less than 100 percent healthy, and that's not the 49ers' biggest concern against the Bengals.
Neither is the fact that starting running back Elijah Mitchell absolutely will not play and the 49ers' run game might struggle big time.
The 49ers' biggest concern is on defense.
They won't have their No. 1 cornerback, Emmanuel Moseley, who will miss the game with a high-ankle sprain. He is by far the 49ers' best cornerback -- he has allowed a passer rating of just 72.6 despite intercepting zero passes. That means his coverage is tight.
His backup, Dontae Johnson, also will not play due to a personal matter.
Which means the 49ers starting cornerbacks will be veteran Josh Norman, who has allowed a passer rating of 101.1 this season, and a rookie -- either Ambry Thomas, who has given up a passer rating of 118.1, or Deommodore Lenoir, who has given up a passer rating of 125.4, and got benched after just a quarter last week when he played in relief of Moseley.
The 49ers have no good options. And the Bengals have two terrific wide receivers -- Ja'Marr Chase and Tee Higgins. Advantage: Cincinnati.
Head coach Kyle Shanahan gave a clue on Monday as to which rookie will start opposite Norman: "Ambry was way behind the eight-ball in training camp. It got him off to a real slow start, D-Mo was ahead of him back then. And I think it's evened out. I think Ambry has really turned it on here in practice this last month or so. He’s been getting better each week and he's definitely got himself a chance to not only push D-MO, but to push the two starters out there too now.”
Sounds like Thomas could make his first career start.
He better play well. The 49ers won't win if he flops.