If he can clear funds by selling Bellerin, the Spanish boss would go ahead with it even though he would want to keep the 25-year-old right-back, who has captained Arsenal in the absence of Pierre-Emerick Aubameyang.
Ceballas made two assists in 24 appearances in the Premier League last season to help the Gunners finish in eighth spot in the table.
Gabriel joined Lille in 2017 and, after loan spells at Troyes and Dinamo Zagreb, he impressed as Lille finished fourth in the curtailed 2019/20 Ligue 1 season.
Gabriel adds to Arsenal's growing Brazilian contingent since the club's former midfielder Edu left his role as coordinator for the Brazilian national team to become technical director past year.
"I spoke a lot with my family and my agents, I also spoke with some of Lille's directors, but as I said, this club's history and traditions and the team project for the next few years were very motivational for my decision to come here".
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While the player has not hinted at a possible exit but with clubs like Bayern Munich and PSG interested in him, Bellerin could very well be tempted to take up a new challenge.
Gabriel, who signed for Lille in January 2017, joins a defence that has also been bolstered by the return of William Saliba from his loan at St-Etienne.
He has many qualities which will make us stronger as a defensive unit and as a team.
So it looks like Ceballos is set to become Arteta's fifth major signing of the summer following the arrivals of Willian and Gabriel while Cedric Soares and Pablo Mari have made their loan moves permanent.
Arsenal, who won the Community Shield last week by beating Liverpool 5-4 on penalties, begin their new Premier League campaign with a trip to Fulham on September 12.