During his two years in the West Midlands, the winger has established himself as a key player, contributing nine goals and nine assists from 78 appearances.
Having failed to appear in just three Premier League fixtures during 2021-22, Buendia featured in every encounter last season as he impressed under Unai Emery.
However, Villa will be without the services of the Argentina international until at least March after he suffered a serious knee injury on Thursday.
Despite the additions that have been made by Emery this summer, the 26-year-old was expected to remain as a first-choice pick for the upcoming season.
Instead, Buendia will begin the process of recovering from sustaining what Villa have described as "significant knee ligament" damage.
In the hours after Villa confirmed the injury in a statement, Emery addressed the situation in his pre-match press conference ahead of Saturday's Premier League opener against Newcastle United.
The Spaniard said: "Yesterday, with the last action in training. It's a six, seven, or eight-month injury.
"It's a tough moment for him, but we want to play on Saturday, thinking to win and be competitive for him."
With Moussa Diaby expected to operate on one flank, Emery must now choose who to deploy on the other with the likes of Leon Bailey, Philippe Coutinho and Bertrand Traore at his disposal.
Reports have emerged that Villa, who will play in the Europa Conference League playoffs later this month, are attempting to secure a deal for Galatasaray attacker Nicolo Zaniolo.
The Italy international starred for the Turkey giants during the second half of last season, chipping in with five goals and one assist from 12 appearances.
Zaniolo is already said to, according to journalist Matteo Moretto, have given the green light to a switch to Villa if a fee can be agreed.