Willian, who will remain with the team at their training base ahead of the final, scored Brazil's final goal in their 5-0 drubbing of Peru in the group stage and scored in their penalty shootout victory over Paraguay in the quarter-finals.
He was brought on for winger Everton at halftime in his side's 2-0 win over Argentina in the last four but tests on Wednesday revealed he had sustained a muscle injury.
Willian of Brazil and Lionel Messi of Argentina talk during the Copa America Brazil 2019 Semi Final match between Brazil and Argentina at Mineirao Stadium on July 02, 2019 in Belo Horizonte, Brazil.
Image credit: Getty Images
Willian was a late replacement in the squad for Neymar, who was forced to miss the tournament in his home country after sustaining an ankle injury in a friendly against Qatar in June.
Willian is Brazil's only absentee for the final at the Maracana, where the five-times World Cup winners will be eyeing their first major trophy since lifting the 2007 Copa America.