Last summer, the West Midlands outfit won the hotly-contested race to acquire the services of the Bayer Leverkusen star in a deal worth in the region of £52m.
Diaby proved to be a valuable additions to Unai Emery's squad, contributing 10 goals and nine assists from his 54 appearances in all competitions.
Holding a long-term contract at the Premier League, the expectation had been that the France international would remain with Villa for at least another campaign.
Instead, it has since become apparent that there is a lucrative proposal on the table from Al-Ittihad, who produced a dismal Saudi Pro League title defence during 2023-24.
While Al-Ittihad are yet to meet Villa's minimal asking price of €55m (£46.21m), there is an understanding that a transfer to the Middle East has become a realistic possibility.
Diaby makes decision over future
According to Football Insider, the 25-year-old has told Villa officials that he would like to make the switch to his Saudi suitors.
There is said to be a "huge" offer on the table for the playmaker, who would be calling time on what many believed would prove to be a productive Premier League career.
Compatriot Laurent Blanc is now at the helm of Al-Ittihad, while Roma playmaker Houssem Aouar has already made the switch to King Abdullah Sports City.
The likes of N'Golo Kante and Karim Benzema are also part of the ranks at Al-Ittihad, something which may have played its part in Diaby's decision-making.
Is this a good deal for Villa?
On the face of it, losing a key player just a season into a long-term contract could be regarded as a significant blow.
From Villa's perspective, though, they seemingly stand to make a profit from a amortisation standpoint, which will stand them in good stead with regards to the Premier League's and UEFA financial regulations.
Furthermore, the money can be reinvested into the squad, with Emery having seemingly given the green light for club officials to try to sign Athletic Bilbao's Nico Williams.
While the likes of Samuel Iling-Junior and Lewis Dobbin have strengthened Villa's numbers on the flanks, a direct alternative will be required for Diaby.