Manchester United are in talks with Porto over a deal for Brazilian full-back Alex Telles.
United manager Ole Gunnar Solskjaer wants to strengthen his options on the left and feels the 27-year-old would be a useful addition.
Porto want £18m for Telles, who has one year left on his contract and could be signed without a fee on a pre-contract in January.
Telles, who has one cap for Brazil, has scored 21 goals in 127 games for Porto.
Solskjaer is set to make a number of changes to his line-up for Wednesday's EFL Cup tie with Brighton, which comes four days after United's dramatic Premier League win over Albion at the Amex Stadium.
The game comes against the backdrop of a continued search for new players, with Borussia Dortmund midfielder Jadon Sancho remaining at the top of the list.
It is understood Sancho is keen to move to United, who are expected to make a final offer for the England international before the transfer deadline on 5 October.
With personal terms and agents fees already agreed, it is likely to be a straight decision by Dortmund, who have repeatedly said they will not sell Sancho after their own 10 August deadline passed without a deal.
Should they maintain that stance, Sancho is prepared to remain in Germany until the end of the season before re-assessing the situation.
Sancho and team-mate Roman Burki did not fly to Munich on Tuesday for their Super Cup match against Bayern because of "respiratory infections" although Dortmund said both players had tested negative for Covid-19.
Meanwhile, after Jose Mourinho noted United's win at Brighton came after the final whistle at the weekend, Solskjaer has responded by pointing out Tottenham have reached the fourth round of the EFL Cup without playing a game.
Spurs were not included in the second round due to their European qualification and then received a bye past Leyton Orient in the third round after their intended opponents' positive coronavirus tests.
"It's a competition you always want to go far in," said Solskjaer. "It depends how you want to get there. You've got teams getting to this round without playing."