Atletico Madrid are reportedly pushing to part ways with either Hector Herrera or Thomas Lemar before Monday's transfer deadline.
The La Liga giants are on the brink of announcing an agreement with Arsenal for Lucas Torreira, who is expected to move to Wanda Metropolitano on a season-long loan deal.
However, Marca has reiterated that a move will only take place if Atletico are able to reduce their playing squad.
While Porto are said to be keen on a reunion with Herrera, the Mexico international is open to fighting for his place at Atletico.
Meanwhile, Lemar has been linked with a switch to a number of clubs playing in major European leagues, including Arsenal and Wolverhampton Wanderers.