Alex Telles and Gabriel Jesus are both feared to have picked up knee injuries which would rule them out of the remainder of the World Cup.
Telles started against Cameroon on Friday but was forced off in the second half after a collision with an opponent, with Jesus leaving the field ten minutes later.
Now, according to Brazilian outlet Globo, medical checks on both players have revealed right knee injuries that will rule them both out of the remainder of the tournament.
Of the two, Jesus' injury is believed to be less serious. Initial checks believe he could need a month to recover which, if accurate, could rule him out of Arsenal's Premier League games against West Ham, Brighton and Newcastle following the conclusion of the World Cup.
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Unfortunately, Telles' injury appears to be more significant. The Manchester United left-back, who is on loan with Sevilla, is believed to need surgery.
Brazil have struggled greatly with injuries thus far in Qatar, with Neymar, Danilo and Alex Sandro all unavailable.
With Telles and Sandro both injured, it was Paris Saint-Germain centre-back Marquinhos who filled in at left-back for the remainder of the Cameroon game. Tite may have to make a similar call for the last-16 clash with South Korea, although there is hope that Sandro will recover in time.
As for Neymar, the Brazilian team doctor has admitted that the PSG man will soon return to light training, after which a decision will be made on his involvement in the remainder of the tournament.