The Rossoneri are reportedly unhappy with the €15m option to buy clause, which would only become an obligation if certain conditions were met. This has led to Milan rejecting the terms outright, with the club pushing for a higher fee.
Gimenez has struggled for fitness and form since joining Milan from Feyenoord in January 2025, managing just seven goals and six assists in 37 appearances. The Mexican has been hampered by an ankle injury since the World Cup, which kept him out of pre-season entirely.
Despite this, Gimenez has reportedly already given his consent to the switch, having held talks with Porto head coach Francesco Farioli. However, this personal agreement does not seem to have swayed Milan's stance on the financial terms.
With Gonçalo Ramos now first choice under Ruben Amorim, Milan see little role for Gimenez this season. Porto will need to improve their offer if they want to get a deal over the line before the window closes.