Amid several changes at both Palace and Villa this summer it was unclear if Guessand could force his way into Unai Emery's plans on his return to Villa Park with the Eagles uncertain over another loan.
Palace had an option to keep Guessand at Selhurst Park after he joined the club on loan under former head coach Oliver Glasner back in January - but that was not activated at the end of the 2025/26 campaign.
He only scored two goals in 14 appearances under Glasner, and new boss Pierre Sage has just secured a deal to trade Brennan Johnson for Dwight McNeil, as part of a low-key few weeks of spending south London.
A change of heart from Sage appears to have propelled the move and Villa have confirmed the loan agreement does include a "conditional obligation to buy" while Palace describe it as an "option to buy".
That final point will need to be clarified from both clubs in the coming weeks as Emery appears happy to let him go and Sage needs convincing over his place at Palace.