Neymar left Tuesday's training session after just 15 minutes with a right ankle injury.
Brazil's doctor says the injury is related to a foul he suffered in Sunday's match and not his recently broken right foot.
Neymar limped as he walked away from the field toward the dressing room.
Doctor Rodrigo Lasmar said Neymar left as a precaution after feeling soreness while jogging.
"What we can do is to calm down," Lasmar said. "A shorter workout was planned for the starters today, they're still in a regenerative process. Neymar trained a little, felt the pain, returned to physical therapy and tomorrow trains normally."