According to Argentine journalist Gaston Edul, Manchester United proposed a loan deal for Martinez. This proposal was met with frustration by Aston Villa earlier this summer.
Edul explained that the Manchester United coaching staff, led by Amorim, were keen on signing Martinez. Unfortunately, Amorim could not convince the club's board that investing in a good goalkeeper was a priority.
Instead, the board told Amorim that they had already signed goalkeeper Yannick Onana and would consider doing a favour by offering Martinez a loan. However, Aston Villa made it clear that they would only sell Martinez if they met certain conditions.
Aston Villa reportedly values Martinez at £40 million. This suggests that the club is willing to sell him if they receive a suitable offer.