Arsenal are seeking a new goalkeeper signing as cover for No1 Bernd Leno.
Leno missed much of the restart after sustaining a ligament strain when he collided with Brighton striker Neal Maupay during the Gunners' defeat in June.
Emiliano Martinez has impressed in his place, having helped Arsenal to five Premier League victories - including against champions Liverpool.
The Argentine was also between the sticks for the Gunners' FA Cup wins over Manchester City and Chelsea as they lifted the famous trophy in Mikel Arteta's first season as a manager.
While Martinez's performances are set to earn him the offer of a new deal, there is uncertainty over Leno's immediate future.
The Sun says Arsenal want further tests on the German's injury and are seeking clarification on how long he will be out for.
And Arteta's staff are looking for potential back-up goalkeeping options ahead of the new season starting next month.