Arsenal have received a double injury boost with Kieran Tierney and Alexandre Lacazette back in training.
The Gunners have had multiple injury concerns this season, and on Sunday, David Luiz suffered a fresh injury setback.
The club have now released pictures on their official website where Tierney and Lacazette were spotted in full training.
Tierney has been out for more than a month with a knee injury, but he could be involved from the off against Villarreal.
Lacazette has missed the past three matches with a hamstring concern, but he could also be involved in the midweek clash.
The Gunners are scheduled to host Villarreal in the second leg of their Europa League semi-final tie on Thursday.
They are trailing 2-1 after the first leg at El Madrigal last week. The Gunners can qualify for the final with a 1-0 win.
Aside from the duo, Pierre-Emerick Aubameyang is fully fit and available after missing four matches due to malaria.