Marquinhos had arrived to the training camp with a minor muscle problem but took part in half of the training session at the Juventus training ground in Turin, Italy.
Brazil will travel from Turin to Qatar on Saturday.
Also on Wednesday, midfielder Bruno Guimaraes needed medical attention after a tackle by Fabinho that ripped off one of his boots, but was able to continue. The 25-year-old Guimaraes scored one of the goals of the training session after the incident.
The five-time world champions, seeking their first World Cup title in two decades, will play their opening game against Serbia on Nov. 24. Brazil then faces Switzerland and Cameroon in Group G.
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