Aston Villa are seen as an attractive option partly because of their financial position after selling Youri Tielemans and Morgan Rogers this summer, and partly because they will offer Champions League football following their Europa League triumph and fourth-place Premier League finish last season.
Unai Emery would need to decide whether he wants to gamble on the up-and-down talent of the 27-year-old, and Leao himself would need to judge whether Villa represent an ambitious enough project to tempt him away from Milan, with the Portuguese still hopeful of interest from one of Europe's traditional giants materialising into something concrete.
Leao made his desire to leave San Siro clear at the end of May, but AC Milan have yet to receive any concrete offers for a player who inspired their Serie A title win in 2021-22.
His stock has fallen sharply since then, with two injury-hit seasons in which he grew increasingly peripheral under managers Paulo Fonseca and Sergio Conceicao, while Massimiliano Allegri's decision to occasionally use him as a makeshift striker did little to help. Despite a €175m release clause, Milan would now be willing to sell for around €60m, and would consider even €50m a good outcome given how far his value has fallen.
The World Cup did little to change the picture. Leao shone only once, in Portugal's win over Croatia, setting up new team-mate Goncalo Ramos, and scored in a 5-0 win over Uzbekistan, but otherwise failed to produce the kind of form that might have attracted a new suitor.
Agents acting on his behalf have sounded out Barcelona and Manchester United, with the club's blessing, but neither approach has developed into formal talks, and with 40 days left before the window closes, time is starting to work against him.
Leao has ruled out both Saudi Arabia and Turkey, despite interest from Galatasaray, Besiktas and Fenerbahce, and despite the presence of his friend Theo Hernandez at Al Hilal, who would welcome him to Saudi Arabia with open arms. For now, the winger appears content to wait and see what develops, even as he prepares to fly out to Australia with the rest of the Milan squad for pre-season training in Perth, starting in around 10 days.
Milan have ruled out leaving Leao behind to train at Milanello, aware that doing so would only further damage his resale value. Only if they can successfully move him on will the club be able to pursue Karetsas, who is valued by Genk at €40m and has already turned down a €30m bid from Borussia Dortmund.