Mesut Ozil is one of six first-team players to return to full training ahead of Arsenal's trip to West Ham in the Premier League on Saturday.
After missing Arsenal's last three matches, Ozil is back in contention to face the Hammers after taking part in Unai Emery's preparations on Wednesday.
His return is a welcome boost for Emery, who has seen his squad – particularly the defence – plagued by injuries in recent weeks, problems that appear to be easing.
Full-backs Hector Bellerin (calf) and Nacho Monreal (hamstring) are back in contention, while central defenders Dinos Mavropanos (groin) and Shkodran Mustafi (hamstring) have also returned.
Laurent Koscielny – who suffered a back spasm during the warm-up ahead of Saturday's FA Cup third-round victory over Blackpool – also took part in training to give Emery a plethora of options to choose from.
Meanwhile, Armenia international Henrikh Mkhitaryan is expected to be back in February after a foot injury.
The Gunners are facing back-to-back London derbies, as they will take on Chelsea the weekend after their match against West Ham.
Arsenal sit in fifth position in the Premier League, three points behind fourth-place Chelsea.