Chelsea has made a proposal of 120 million euros (£105.6 million) for Benfica's Argentina midfielder Enzo Fernandez, which would make him the British transfer record signing.
So far, no word on whether the Blues' offer, which is understood to involve instalments, would be accepted.
If the deal goes through, it will cost more than the £100 million Manchester City paid Aston Villa for Jack Grealish in 2021.
During Argentina's World Cup victory in Qatar, Fernandez was awarded the tournament's youngest player.
Benfica had previously accused Chelsea of attempting to unsettle the player, with the Portuguese side's manager Roger Schmidt declaring their pursuit "closed".
However, it is unlikely that the Premier League team would have made a new offer unless given some indication that it may be accepted.
Fernandez joined Benfica from River Plate in August for a reputed £10 million and has scored four goals in 29 appearances for the Primeira Liga club.
During the World Cup, he scored Argentina's second goal in a 2-0 group-stage win over Mexico.
In January, Chelsea signed Noni Madueke, Mykhailo Mudryk, David Datro Fofana, Andrey Santos, Benoit Badiashile, and Malo Gusto on permanent contracts and loaned Joao Felix to Atletico Madrid.
It follows a summer in which they spent a Premier League record £270 million - the second-highest summer spending by any club in the world behind Real Madrid (£292 million) in 2019.