The left-back is out of contract in less than a year and can sign pre-contracts in January.
United have bid €15 million, per Portuguese and English reports.
But A Bola claims Porto have 'not been seduced' by the bid from United.
They want more money, or Telles will remain at the club beyond this transfer window.
United will be hoping to convince a deal, and talks could go down to the transfer deadline.