Mesut Ozil could miss out on Arsenal's crunch match against Liverpool after the playmaker was a conspicuous absentee when the squad landed on Merseyside.
The former Germany international has been in and out of the Gunners team during a tough start to the 2018-19 season.
And he suffered another setback when he was substituted at half time in Wednesday's 1-1 draw against Brighton.
Now, Ozil runs the risk of being left out of the Arsenal squad altogether when they take on the table-topping Reds at Anfield.
The playmaker was nowhere to be seen on Friday when Unai Emery and the rest of the Arsenal side filed off the coach after arriving in Liverpool.
Arsenal are yet to announce their final squad list for the clash, with the north Londoners determined to take a victory and fend off newly resurgent Manchester United, now just six points behind the fifth-placed Gunners.
Elsewhere, Emery will have to wait until the last minute to find out the fate of three key members of his backline.
Shkodran Mustafi, Nacho Monreal and Hector Bellerin face late fitness tests ahead of Saturday's crunch clash.
Arsenal have won one of their past four games in all competitions amid a defensive injury crisis that has seen Unai Emery forced to use Ainsley Maitland-Niles at the back.
But Mustafi, Monreal and Bellerin could give the Arsenal boss a boost for Saturday's visit to Anfield, with Liverpool six points clear at the top of the Premier League.
Arsenal said in a medical update on Friday that Monreal and Mustafi will have right hamstring injuries assessed ahead of the game, with Bellerin's left calf also to be tested.
Mustafi last played in the 1-0 win over Huddersfield Town on December 8, while Bellerin has been out since a 3-2 loss at Southampton on December 16 and Monreal missed the Boxing Day draw with Brighton and Hove Albion.
Liverpool will be without defender Joe Gomez and vice-captain James Milner, with the latter struggling to recover from a muscle injury.
But Mohamed Salah will be available to Jurgen Klopp after the Egypt star avoided punishment for winning a contentious penalty in the Reds' defeat of Newcastle United on Wednesday.