Arsenal boss Unai Emery is attempting to convince Laurent Koscielny to remain with the club this summer.
The Gunners captain refused to join the team on their pre-season tour of the United States after his request to cut short his contract by a year, which would allow him to return to his native France on a free transfer, was denied.
Per MailOnline's Jonathan Spencer, after Arsenal's 1-1 draw with Angers on Wednesday, Emery said:
"Koscielny is a very important player for us, and I don't lose hope for him to be with us next season.
"I am speaking regularly with him, and I am trying to convince him to stay with us.
"But at the moment his first idea is still to leave, and this situation is making us change our ideas about the centre-backs."
Arsenal have signed William Saliba this summer, but as part of the deal, he has been loaned back to Saint-Etienne for the duration of the campaign.
As football journalist Layth Yousif observed, Arsenal's situation in central defence is far from ideal:
Konstantinos Mavropanos and Rob Holding are working their way back to fitness, while Calum Chambers spent last season on loan with Fulham, who were relegated having conceded 81 goals. Shkodran Mustafi has yet to convince since his arrival from Valencia in 2016.
Sports journalist Uche Amako said the Gunners' need to sell the German during Arsenal's 3-0 win over Fiorentina in July:
Mustafi featured in the match as part of a back five, but despite the team keeping a clean sheet, Football.London's James Benge was not convinced:
Koscielny will be 34 in September, but whether he stays or moves on will be significant to Arsenal, as Emery added:
"It makes a big difference to us if Laurent plays or not. The transfer window closes in eight days and we need to speak about what we do now.
"We want to be strong in the defensive line and we are thinking about how we can replace him.
"If we can sign one more centre-back it will only be if he is clearly better than the six we already have."
Arsenal have conceded a combined 102 goals in the past two Premier League seasons, so improving at the back this summer was already a priority before the Koscielny situation arose.
The Frenchman is past his prime, but the Gunners cannot afford to lose him if there are no new arrivals for the team to call upon this season.