49ers roster: Why Ambry Thomas takes over as starting cornerback

San Francisco 49ers, Ambry Thomas (Photo by Rey Del Rio/Getty Images)
San Francisco 49ers, Ambry Thomas (Photo by Rey Del Rio/Getty Images) /

The 49ers drafted Ambry Thomas in the 3rd round to be a future starter at cornerback, but Niner Noise details how the future might come just this year.

For how talented the 49ers defense has been the last couple of years, there has been a constant revolving door at the second cornerback position. Even back in 2017, the first spot seemed locked down by Ahkello Witherspoon, while the second spot was constantly changing.

In 2018 and 2019, that first spot was held down by Richard Sherman while several players, including Witherspoon, Emmanuel Moseley, and the spurts of Jason Verrett attempted to fill in. In 2020, as Verrett coupled his ability with health for the first time, Sherman got hurt as well, causing another revolving door.

Now heading into 2021, the 49ers have 4/5ths of their secondary comfortably in place with returning starters Verrett, nickel back K’Waun Williams, free safety Jimmie Ward, and strong safety Jaquiski Tartt. That leaves only the second cornerback position.

Down the stretch last year, Ahkello Witherspoon was the starter and played decently well all things considered, but he’s now in Seattle. Richard Sherman was not re-signed by the 49ers, and following recent events that have transpired, it seems unlikely a reunion will occur. Dontae Johnson and Tim Harris are both depth pieces that could conceivably compete for the position, but it seems unlikely.

5th-round rookie Deommodore Lenoir is already set as a nickel back, which leaves only 2 players left for the position – Emmanuel Moseley and Ambry Thomas. Moseley has the leg up heading into training camp, but here’s why Thomas might be able to nab the starting spot from him.

49ers coaching staff’s trust in Emmanuel Moseley

CB Emmanuel Moseley was a large factor in the 49ers Super Bowl run in 2019, filling in for an injured Ahkello Witherspoon and never relinquishing the starting spot, starting for the large majority of the playoffs. Despite this, in 2020, Moseley got off to a rough start and even after Sherman was injured, didn’t seem to gain much traction with the coaching staff. Just looking at his snap counts from 2020 indicates exactly how tumultuous his playing time has been.

Emmanuel Moseley’s Snap Counts
Def.Def.ST SST S

Provided by Pro-Football-Reference.com: View Original Table
Generated 7/26/2021.

As the chart indicates, Moseley was a starter at outside cornerback up until roughly after the bye week, where his playtime diminished. Following his hamstring injury, he was relegated to pure backup status. For a team that doesn’t typically use injury as a qualification to bench a player, as with Ahkello Witherspoon and Moseley in 2019, the 49ers benching Moseley perhaps speaks to their valuation of him.

And yes, while Moseley did receive the second contract, it was a smart decision given that he was a restricted free agent. Moseley won’t be getting cut, but his new contract is not a guarantee of any starting role.

Defensive fit against the NFC West

The biggest knock against Moseley, and against most cornerbacks, is his play when against large physically imposing WR1s, of which the NFC West, unfortunately, has two of the best in D.K. Metcalf and Deandre Hopkins. In both games against these two that Moseley played in, both the Cardinals and Seahawks were able to target Moseley relentlessly.

While no one is expecting Moseley to lock down these receivers, the ease in which they managed to dice him up and beat him does create a weakness for the 49ers’ defense. The rookie Ambry Thomas on the other hand seems to excel in the type of physical press coverage required against these types of players.

Of course, these top-tier receivers will prove a challenge for any cornerback, but as this draft profile from the Draft Network of Thomas indicates, he excels in a press-heavy man coverage scheme, a scheme that the 49ers used more with Robert Saleh down the stretch and one that new DC DeMeco Ryans plans to implement as well.

The 49ers are moving towards a more varied and aggressive defensive look under DeMeco Ryans, one that will likely reward man coverage and bump and run technique. That’s a defensive style that does not fit Emmanuel Moseley but does fit Ambry Thomas.

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Moseley has been a stellar find for the 49ers and will have value to the team no matter what he does, but Thomas’s fit on the defense seems to indicate that he’ll be the stopgap at that second cornerback roundtable sooner rather than later.