A fourth round pick in 2019 from USC, Marshall competed for a roster spot as part of a deep corner back rotation led by Marlon Humphrey, Marcus Peters, Tavon Young and Jimmy Smith.
Marshall spent most of his rookie season on injured reserve, but he was activated to the 53-man roster in November and he appeared in three games. While playing just four snaps on defense, Marshall played 43 snaps on special teams.
In other injury-related news, Harbaugh said wide receiver Chris Moore suffered a broken finger. Moore, who pitched three passes for 21 yards last season, is a standout at special teams.
“It’s great, the same thing happened last year,” Harbaugh said. “Chris knows how to handle that. He’ll be fine, but it’s going to be a few weeks until that bone heals.”
Defensive approach Brandon Williams and outside linebacker Jaylon Ferguson were the other two players not at Monday’s practice, but Harbaugh said they will be back in a few days on most days.
