And the South American giants team doctor Rodrigo Lasmar claims the unspecified injury was caused by a hotel bed.
On Wednesday, he earned the start for his country, becoming the first-ever active Whitecaps FC player to appear in a World Cup match. Once he feels good to train, he will return and immediately be ready to play.
The night didn't go according to plan for Marcelo though who had to go off after just nine minutes with a shoulder injury and while there was concern at the time, it doesn't appear as though it is a serious problem.
Brazil's team doctor has offered a weird excuse for why defender Marcelo was substituted during the country's final group match against Serbia on Thursday.
Neymar's World Cup has consisted of theatrical dives, arguments with referees and a few tears. "It's all under control".
Mexico face Brazil in a round-of-16 clash in Samara on Monday, and Guardado issued his appeal amid criticism of Neymar for going to ground easily during the tournament.
"Hi guys! As you know, I celebrated the last victory so much that I even got injured", the 22-year-old said.
"Thank God it wasn't anything serious", Marcelo said on Instagram.
Doctors also had to take care of coach Tite, who pulled a muscle while celebrating one of the team's goals against Costa Rica. However, Douglas Costa will miss the game, having suffered a thigh injury after coming off the bench against Costa Rica.