The names of the infected players were not disclosed. Others to test positive included six of Flamengo's support staff, two workers from companies contracted by the club and 25 family members of players and employees.
Flamengo have reached a deal to extend the contract of their Portuguese head coach Jorge Jesus, according to widespread media reports.
The 65-year-old, whose deal was due to expire this month, will be tied to the Rio de Janeiro club until June 2021, the Globo newspaper reported, writes Xinhua news agency.
He is said to have accepted an annual salary of four million euros – a 50 per cent increase on his current deal.
The contract includes an exit clause that would allow Jesus to join a European club, should he receive an attractive offer, reports said.
The former Benfica and Sporting Lisbon boss guided Flamengo to the Brazilian Serie A and Copa Libertadores titles in 2019, having joined the club last June.