Arsenal boss Mikel Arteta has acknowledged that Edu's decision to leave his role as sporting director had come as a surprise.
Since the former Gunners midfielder was appointed in the position in November 2022, the club have been on an upward trajectory both on and off the pitch.
The Brazilian has overseen a number of crucial deals to help transform Arsenal into contenders for the Premier League title, Arteta's side finishing runners-up in the past two seasons.
However, on Monday, it was revealed that the 46-year-old would be stepping down from his position, the development regarded as a significant blow to the progress of the North Londoners.
As it stands, the current expectation is that Edu will take on a role working for the multi-club network of Nottingham Forest and Olympiacos owner Evangelos Marinakis.
As per The Guardian, Arsenal failed in an effort to tempt Edu into staying in the capital with the offer of an improved contract.
What has Arteta said on Edu?
Speaking to reporters ahead of Arsenal's Champions League fixture against Inter Milan on Wednesday night, Arteta acknowledged that he had not been anticipating such a change behind the scenes.
The Spaniard said: "Everything happened very quickly. Obviously I loved working with him and really enjoyed being alongside him on this incredible journey.
"From day one we have been together and I'm very grateful personally for all the work he has done for the football club.
"We both had this special chemistry and really enjoyed working together. He has an amazing opportunity now to do something else in a different role and he believes that is the right professional move for him. We have to respect that and everyone wants the best for him."
Arsenal's hierarchy will now work to appoint a replacement, the assumption being that the successor will be in place in time for the January transfer window.
Return to form imperative for Arsenal
Edu's exit has coincided with Arsenal enduring an indifferent run of form with their last Premier League success coming at home to Southampton on October 5.
Since then, the only two victories in five have been against Shakhtar Donetsk and Preston North End in the Champions League and EFL Cup respectively.
Before the international break, Arteta takes his Arsenal squad to play Inter Milan at San Siro and Chelsea across the capital at Stamford Bridge.
Sitting seven points adrift of leaders Liverpool in the Premier League table and in ninth position - albeit with a game in hand - in the Champions League standings, Arteta will feel that it is imperative that his players deliver potentially-pivotal results over the next two games.