Arsenal midfielder Santi Cazorla took part in a light running session on the Emirates pitch on Thursday evening.
The Spaniard was spotted training with head of performance Shad Forsythe ahead of the Gunners' Europa League semi-final against Atletico Madrid.
Sky Sports News understands he remains highly unlikely to play this season as he continues to recover from an Achilles injury.
His last appearance for Arsene Wenger's side came in October 2016 when Arsenal beat Ludogorets 6-0 in a Champions League group stage match at the Emirates.
The 33-year-old has been recovering in Spain and has had 10 operations to heel his injury. At one stage it was feared his foot would have to be amputated due to an infection.
Cazorla's contract expires at the end of the season and Gunners boss Wenger said recently "they would assess his fitness before making a final decision on his future".
Arsenal will travel to Madrid next Thursday for the second leg of the semi-final at the Wanda Metropolitano.