Brazil manager Carlo Ancelotti says Gabriel will be assessed on Sunday after the Arsenal defender suffered a groin injury in a friendly win over Senegal in London.
The 27-year-old pulled up off the ball just before the hour mark and received treatment to his right thigh before being substituted.
Gabriel has formed a key part of the Arsenal defence as they top the Premier League table, having conceded just five goals in 11 league games.
The Gunners face North London rivals Tottenham on 23 November before welcoming Bayern Munich in the Champions League the following Wednesday.
“Bad? I don’t know. He had an injury in his adductor,” said Ancelotti. “The medical staff has to check tomorrow.
“We are really sorry for this, really disappointed. When a player has an injury, you hope they can recover well and soon.”
Brazil beat Senegal 2-0 at Arsenal’s Emirates Stadium through goals from Chelsea’s teenage winger Estevao and Manchester United midfielder Casemiro.
Meanwhile, Italy boss Gennaro Gattuso says Arsenal defender Riccardo Calafiori has left the international camp.
He did not play in Italy’s World Cup qualifying win over Moldova on Thursday, having been following an individual training programme for load management.
“We tried Calafiori, he had a few issues,” Gattuso told Sky Sports Italia, external before Italy’s match against Norway on Sunday.
“I thank him for his commitment. He stayed here for a week, he could have played perhaps, but it wouldn’t have been fair to him or Arsenal.”
A source told BBC Sport that Calafiori has not returned to Arsenal for any treatment.
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