Having arrived with such high expectations – and an equally high transfer fee (reportedly £28 million) – the 19-year-old has struggled to settle since arriving in England.
The Frenchman is yet to feature for the Arsenal first team but a loan move back to his home country could allow him to reestablish his highly regarded reputation.
So what does Saliba need to do to make it Arsenal when he returns?
Get more senior minutes under his belt
The first thing Arsenal did after signing Saliba, was to loan him straight back to Saint-Étienne. As much as this was done to meet the demands of the Ligue 1 club, it also gave Saliba a season to develop.
Unfortunately, injuries and the pandemic meant Saliba didn't gain as much game time as he would have liked. He made just 12 league appearances before the season was abruptly cancelled last April.
In part, taking this into account, Arteta decided it was best that Saliba continued his development out of the limelight, featuring only for Arsenal's under 23 team.
After a frustrating few months, both parties seemed to agree that this level wasn't quite satisfactory for the player. So Saliba now has a chance to get more senior minutes under his belt at Nice.
This seems to be the first, simplest, and yet most important step.
Impress at Nice
As it stands, Nice sit 12th in Ligue 1 and look like they are set for a mid-table finish.
It's likely that the loan deal was made with a guarantee of some minutes, but Saliba will still have to perform well to establish himself in a defence which has conceded 22 goals in 16 games.
Having already proven himself to be on of the league's most promising players once before, this is a task Saliba will hope to do with ease.
Prove that he can be right for Arteta
When Arsenal signed Saliba back in July 2019, Unai Emery was their head coach and Raul Sanllehi was the man in charge of transfer dealings. Both men have now departed, and Arteta, as manager, is very much the one calling the shots.
It seems Arteta is yet to be convinced by Saliba, and some reports have suggested he still regards the teenager as an "Emery signing". While it's true Arteta played no part in signing the Frenchman, there's been ample time for him warm to Saliba like he has to other players.
Kieran Tierney was also an "Emery signing" but there is no doubt Arteta now very much considers him to be a key part of his team.
So Saliba must return for his loan, with plenty of game time under his belt, and prove to Arteta that he is ready to be an integral part of the squad.