Manchester United are reportedly looking to pay less than half of Porto's asking price for Alex Telles.
With his contract due to expire in 2021, the attack-minded left-back is likely to leave the Portuguese giants this summer.
However, according to TVI 24, the Premier League giants are currently offering less than £9m for the 26-year-old.
Porto are said to have no interest in a sale at that price, instead preferring to risk losing their key man on a free transfer at the end of the season.
United have allegedly been informed that it will take a bid of £18m to get a deal over the line.