Solet, 26, joined Udinese from Red Bull Salzburg last summer and has established himself as one of the standout performers in Serie A, starting all 33 of his competitive appearances and contributing three goals and one assist.
At 1.93 metres, he is a physically imposing presence who has been central to Udinese's solid defensive organisation.
Inter face a significant defensive rebuild. Francesco Acerbi and Stefan de Vrij will both leave when their contracts expire in June, leaving at least two vacancies in the back line. Alessandro Bastoni's future is also uncertain given Barcelona's interest.
Udinese are asking for €25 million plus bonuses, a figure backed by a structural agreement with the player's camp: if no offer matching that valuation arrives before the window, Solet will sign a new bridge contract at a significantly higher salary, extending beyond 2027 and strengthening Udinese's negotiating position further.
Inter are considered clear favourites ahead of AC Milan, Roma and a cluster of Premier League clubs that have all been scouted the player.
A legal hearing in April was identified as a key milestone in Inter's decision to proceed, with the outcome understood to have given the green light to their pursuit.