Sherman suffered a Grade 1 hamstring strain in practice Friday, 49ers coach Kyle Shanahan said Sunday. Sherman will be out at least a week, Shanahan said, and he won't play in the team's preseason opener against the Dallas Cowboys on Thursday.
The veteran cornerback felt his hamstring tighten up after falling during Friday's practice and had to leave the field.
Sherman joined San Francisco in March on a three-year deal after his release from the Seattle Seahawks, where he was a three-time All-Pro selection and four-time Pro Bowler in seven seasons.
In other 49ers injury news, guard Joshua Garnett has received multiple opinions on his injured knee, and the 49ers will give him the week off to rest, Shanahan said.