He suffered the injury with 13:30 remaining in their 31-17 loss to the Tampa Bay Buccaneers.
He had 19 rushes for 59 yards and two touchdowns and four catches before the injury, which occurred during a 7-yard touchdown run. He walked off the field with a limp after the touchdown and did not return.
The Panthers made McCaffrey the NFL’s highest-paid running back during the offseason with a four-year, $64 million extension.
McCaffrey is coming off a 2019 season in which he became the third player in NFL history to have 1,000 yards rushing and receiving in the same season.
ESPN’s David Newton contributed to this report.