Gabriel returned in the EFL Cup win over Nottingham Forest on Tuesday and is ready to fight for his place.
“I think this season the competition has been and will continue to be very strong, with so many great defenders at the club," he told Arsenal Player.
“If a player is at Arsenal it must mean they are great, and whoever the manager picks to be in the starting XI is good enough to be there.
“The fight to get a place in the team will be a good fight, and Arsenal benefit from this competition between players.
"Us players will always try to get a place in the team.
“I'm going to train very hard to try and get in the team, to get in the starting XI, while at the same time showing respect to my team-mates."