The Spaniard trained with the rest of the Arsenal team on Wednesday ahead of their game with Sporting CP in the Europa League.
Monreal, 32, has been sidelined with a hamstring injury for the past month, though is now back training with Emery & Co.
The defender still remains a doubt for the Group E match, though will be assessed by medical staff ahead of the fixture.
Sokratis will also face a fitness test before the tie.