"As of right now he is listed as day-to-day,'' coach Matt Rhule said on Monday as he began preparing for Tampa Bay.
Rhule declined to expand, citing respect for McCaffrey's privacy.
The injury came with 1:10 remaining in the game when safety Daniel Sorensen slammed McCaffrey to the ground near the sideline after a 1-yard catch. McCaffrey immediately left the game, and team trainers began checking the shoulder.
McCaffrey returned for one more play with nine seconds left but was not made available to the media afterward as he underwent treatment. He was scheduled for tests on the shoulder Monday morning.
Sunday was the first game for the NFL's highest-paid back after he missed six in a row with a high ankle sprain suffered in a Week 2 loss at Tampa Bay.
McCaffrey made his presence felt with 69 yards and a touchdown on 18 carries and 82 yards and a touchdown on 10 catches. He played 71% of the snaps, with Mike Davis, his replacement the previous six weeks, getting 31%.
McCaffrey provided a boost in the red zone, where Carolina (3-6) has struggled. The Panthers were 4-for-4 in scoring touchdowns inside the Kansas City 20 to improve to 8-for-9 on the season with McCaffrey in the lineup.
The Panthers are 10-for-21 in scoring touchdowns in the red zone without the eighth pick of the 2017 draft.
McCaffrey did not miss a game during his first three seasons, including last season, when he became the third player in NFL history to have 1,000 yards rushing and receiving in the same season.
He's now in danger of missing his seventh game since signing a four-year, $64 million extension that averages $16 million a year.
The Panthers are 0-3 this season with McCaffrey and have lost 11 straight with him going back to last season.