USC football training camp: Defensive backs breakdown

There’s no denying there is a lot of potential in USC’s defensive secondary. But it’s not the most experienced group, with one senior and three juniors (two of which are walk-ons) in the secondary.
Here is a breakdown of where USC stands at defensive back entering 2019:
Key returners: Dominic Davis (Sr.), Olaijah Griffin (So.), Talanoa Hufanga (So.), Greg Johnson (So.), Isaiah Pola-Mao (So.), C.J. Pollard (Jr.), Raymond Scott (So.) Isaac Taylor-Stuart (Fr.), Chase Williams