McCaffrey was getting his lower left leg worked on during the first half of Sunday's game in Atlanta, Nick Wagoner of ESPN.com reports.
McCaffrey took a big hit on the 49ers' first possession of Week 7 action after a 24-yard catch, but he continued to play through it until the team's third drive, when he remained on the sideline to get worked on. For as long as McCaffrey is sidelined, Kaelon Black will be San Francisco's primary RB.