Arsenal boss Mikel Arteta admits they have an injury concern for Gabriel.
The defender is struggling to be fit for the Premier League kickoff in a fortnight's time.
Arteta, after their friendly defeat to Chelsea, said: "We don't know [whether he will be available for Brentford]. He's still injured. He picked up and injury while he was doing the preparation for the Olympics with Brazil and at the moment he's not been able to train with us. That seems unlikely at the moment but hopefully he can recover quickly."
on Bukayo Saka, the manager added: "He's back very soon. He needed some holidays, he needed to be away. He had an incredibly busy year and he will be back with us in the next few days. We're looking forward to seeing him."
