San Francisco 49ers Must Hope Rookie Cornerback Can Survive Trial By Fire

The San Francisco 49ers face another high-leverage game in their fight to secure a playoff berth and go into it severely depleted at a key position group.

San Francisco faces a challenging Week 14 road game with another playoff contender, the Cincinnati Bengals, in a matchup between two teams who saw their postseason hopes damaged by postseason losses. The 49ers were stunned by the Seattle Seahawks in a wild game while the Bengals suffered a home defeat to the Los Angeles Chargers.

It was a painful loss for the Niners, who suffered more injuries in Seattle. Running back Elijah Mitchell sustained a concussion, which, along with a knee issue, has ruled him out against Cincinnati. Emmanuel Moseley suffered an ankle sprain, pressing the pause button on a stellar campaign for the cornerback.

Mitchell’s absence, which would be compounded if Deebo Samuel—listed as questionable—is unable to return from a hamstring problem, is a significant blow to the run game. However, San Francisco managed 9.5 yards per pass play last week and succeeded in moving the offense even without an efficient rushing attack.

Of greater concern is the loss of Moseley, which was magnified when backup Dontae Johnson was ruled out on Saturday due to a personal matter.

It leaves the Niners choosing between two rookies, third-round pick Ambry Thomas and fifth-round pick Deommodore Lenoir, to start across from Josh Norman.

Thomas has played largely on special teams this season while Lenoir, having impressed when pressed into action early in the season, was benched after Week 3 and his lack of time on the field was apparent against Seattle as he gave up a downfield reception to D.K. Metcalf, was flagged for pass interference in the red zone and conceded a touchdown to D’Wayne Eskridge after filling the void left by Moseley’s injury.

Picking between Thomas and Lenoir is an unenviable task for the Niners as their defense prepares to face one of the most talented receiving corps in the NFL.

The Bengals rank a disappointing 20th in Expected Points Added per play on offense, per rbsdm.com, yet the impact of the trident of Ja’Marr Chase, Tee Higgins and Tyler Boyd is better illustrated by Cincinnati’s ranking of eighth in the NFL in Explosive Pass Rate, per Sharp Football Stats.

San Francisco is 19th in the NFL in Explosive Pass Rate allowed and now has razor-thin depth in an area of the team that was already considered a weakness.

Either Thomas or Lenoir will be thrown into the fire and there isn’t much reason for the Niners to have confidence in the man starting at the other outside corner spot, Norman continually enduring significant struggles in coverage since joining the team in September.

The 49ers’ defense has improved over the last four games and is now ranked seventh in Football Outsiders weighted DVOA. What is unclear is whether that improvement can be sustained without Moseley, whose reliability in coverage made him a significant contributor to those positive strides.

Against a still extremely vulnerable Bengals offensive line that is 27th in Football Outsiders Adjusted Sack Rate, the 49ers’ may lean on the defensive front, the depth of which is in stark contrast to that of the defensive backfield, to protect their fragile secondary.

Yet there is no doubt that at some point either Thomas or Lenoir is going to receive a stern test from the Bengals’ fearsome receiving trio. In a game FiveThirtyEight rates as the most important of Week 14 in the race for the playoffs, it is imperative whoever the Niners choose to start in Moseley’s place stands up to that challenge.