The San Francisco 49ers are preparing for their Week 18 contest against the Seattle Seahawks on Saturday at Levi’s Stadium in Santa Clara, California.

Running back Christian McCaffrey and left tackle Trent Williams typically receive rest days during the first practice of the week, and neither participated on Tuesday. This time, though, it was health-related.

McCaffrey is dealing with back stiffness—an issue that surfaced before a previous game and flared up again on Sunday night against the Chicago Bears. However, neither head coach Kyle Shanahan nor McCaffrey sounded overly concerned, and the running back is expected to be available against the Seahawks.

“I know it was sore just from Sunday night, so that’s why we got him [not practicing] today.”

When asked if the back issue could be serious, McCaffrey responded, “No, not serious.”

Williams sustained a hamstring injury against the Bears. While Shanahan did not specify the severity, he has not ruled out the veteran lineman for Saturday’s matchup.

Fullback Kyle Juszczyk (hip) and defensive end Keion White (groin) also exited Sunday’s game with injuries. Neither practiced on Tuesday.

The positive news is that tight end George Kittle returned to practice after missing last week and sitting out against Chicago. Still, Shanahan cautioned against assuming that means the All-Pro will suit up this weekend.

“I mean, we’re barely moving today,” Shanahan said. “It’s a walkthrough, so [with] the short week we’ve got, we won’t be doing much all week.”

Cornerback Renardo Green, who missed the past two games with a neck injury, was a full participant on Tuesday.

Below are Tuesday’s practice participation reports for both the 49ers and Seahawks, which were provided by the 49ers Communications staff.

San Francisco 49ers Tuesday Practice
Did Not Participate In Practice

FB Kyle Juszczyk (hip)
RB Christian McCaffrey (back)
DE Keion White (groin)
T Trent Williams (hamstring)

Limited Participation in Practice
Full Participation in Practice

Seattle Seahawks Tuesday Practice
Did Not Participate In Practice
Limited Participation in Practice
Full Participation in Practice