The Gunners had 24 players registered already for the competition after successfully navigating their way through the group phase.
As per UEFA rules they are now permitted to add a further three members to their squad to be eligible for selection in the later rounds.
Returning loanee youngster Eddie Nketiah is the third addition to the squad ahead of Arsenal’s last-32 tie with Olympiakos.
Arsenal travel to Greece in the first leg of the tie on February 20, before Olympiakos visit the Emirates a week later.
The Europa League has taken on increased importance for Arsenal this season, given there is a spot in next seasons Champions League at stake.
With the Gunners’ Premier League form stuttering, they are unlikely to finish in the top four, and currently face a battle to qualify for Europe at all next season.
A loss in their return to domestic action against Newcastle would see them slip into the bottom half of the table.
Arteta is keen to make use of the winter break before then as best as possible, and heads to Dubai with his side for a warm-weather training camp this week.
The squad are due to depart for the Middle East on Thursday, and Arteta has even allowed his players to invite their families and children along.
He is hoping to boost team spirit and unity by having everyone eat together on one evening of the trip.
Some of Arsenal’s players have already touched down in United Arab Emirates for a few days rest ahead of the busy schedule.
They’ll then be training from Friday through to Tuesday, before returning to the UK in order to prepare for the Newcastle clash on February 16.