A deal for the Ecuadorian full-back had appeared all but done. Transfer expert Matteo Moretto, speaking on Fabrizio Romano's YouTube channel, revealed that AC Milan and Aston Villa had reached a near-total agreement, with only minor details left to finalise before signatures and an official announcement.
Then the picture changed: during an internal Milan meeting, Amorim asked the club to hold off on giving final approval, wanting to evaluate Estupiñán in training himself before deciding whether he fits into his plans for the season, a request that has frozen talks with Aston Villa in their tracks.
Estupiñán's first season at Milan was largely underwhelming, his derby winner against Inter standing out as the lone highlight, and he has since lost his starting spot at left wing-back to Davide Bartesaghi, making his uncertain path out of the club all the more striking given how close the Villa deal had come; Unai Emery, who previously coached him at Villarreal, is keen to reunite with him in the Midlands.
What happens next depends largely on Amorim's verdict after watching him train over the coming days, while Aston Villa must decide whether to wait on Milan's timeline or look elsewhere.
Santiago Giménez remains a separate headache for Milan's business. The Mexican striker is currently sidelined with injury and missing the club's tour of Australia, though he did stay behind at Milanello and is due to attend Franco Baresi's funeral; for now, he appears focused on winning over Amorim rather than leaving.
Even so, exit speculation continues to build. Porto have shown the most concrete intent, reopening contact with Milan to make Giménez available to coach Francesco Farioli, according to A Bola, with talks reportedly being facilitated by agent Jorge Mendes, who also brokered Milan's deal to sign Gonçalo Ramos from Paris Saint-Germain.
Porto, however, appear to be thinking loan, potentially with an option to buy, a structure Milan consider insufficient; the club's stance could shift only if a buy-back obligation were attached, possibly tied to sporting targets such as winning the league or reaching the Champions League.
Lazio remain in the background too, with Rino Gattuso's side keeping Giménez on their list of options to strengthen the attack.