Marcelo limped off the field in the 10th minute of Wednesday's game against Serbia.
In the knock-out phase, Switzerland will play against Sweden, while Brazil will play against Mexico.
The Costa Rican players have been heavily criticized back home and will hope to turn the pages to give their people something to cheer about.
Brazil defender Marcelo's mysterious injury that has left his FIFA World Cup participation in doubt for the rest of the tournament has been explained. The midfielder hinted he was not used to this type of training load with his team in China.
The 26-year-old Paris Saint-Germain forward had surgery on a foot fracture at the start of March and did not play again until Brazil's 2-0 friendly win over Croatia three weeks ago, when he came off the bench to score.
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Brazil eventually won 2-0. "It's all under control".
Brazil are up against Serbia and the latest result in the Group F will be a booster for Serbia who need 3 points to qualify and a warning to Brazil who need just a point to advance to the last 16.
The Brazilian soccer federation said Marcelo had improved from its back problem but did not provide a timetable on his recovery. "I'll be back in action soon".