49ers roster 2021: Bubble watch ahead of preseason Week 1

49ers Bubble Watch: Cornerback

Lock: Emmanuel Moseley, Ambry Thomas, Jason Verrett, K’Waun Williams

Strong Bubble: Dontae Johnson, B.W. Webb, Deommodore Lenoir

Weak Bubble: Alexander Myres, Ken Webster

Long Shot: None

Unlike safety, where they have a number of veteran starting options to fill in for injuries or underperformance, the Niners have a top-heavy group of cornerbacks with more than enough question marks about the depth.

Simply put, San Francisco has to hope its trio of Jason Verrett, Emmanuel Moseley and K’Waun Williams stays healthy this season and plays at a high level. Given Verrett and Williams’ injury histories, though, either one of two things needs to happen.

Dontae Johnson needs to stay healthy and play adequately enough or the rookie, Ambry Thomas, needs to develop quickly.

Thomas has had up-and-down moments during training camp, so his on-field efforts during the preseason will be worth monitoring closely. Especially with fellow rookie Deommodore Lenoir struggling to make much of an impact, which potentially explains why the 49ers onboarded two more veterans this offseason, B.W. Webb and Alexander Myres, who’ll be battling for potentially just one final reserve spot on the 53-man roster.