Enzo Fernandez could become the Premier League’s most expensive player if Chelsea land the Benfica midfielder for a reported 120 million (£105.5m) fee.
The previous record was set by Manchester City following the signing of Jack Grealish for £100m in August 2021.
However, Chelsea could also make a late bid for Brighton’s Moises Caicedo, who has been linked with Arsenal for much of the last month.
The south coast club turned down Arsenal’s initial £60m offer, and have since been adamant the Ecuador international will remain at the club for the rest of the season.
But Fernandez is likely to be the latest in a string of new arrivals at Chelsea, who have spent over £450 million on transfers since the conclusion of last season.
Joao Felix, Benoit Badiashile, David Datro Fofana, Mykhailo Mudryk, Andrey Santos and Noni Madueke have already arrived at Stamford Bridge this month.
Tottenham remain cautiously optimistic about finalising a transfer for Sporting Lisbon defender Pedro Porro ahead of the deadline, the PA news agency understands.
Elsewhere, Manchester City are not expected to be busy on deadline day despite the shock proposed loan move of Joao Cancelo to Bayern Munich.
Similarly, Manchester United appear to have completed their business apart from the possibility of one or two fringe players going out on loan.
Newcastle completed the signing of Anthony Gordon from Everton, but could still be active in the window.
Jonjo Shelvey is expected to become a Nottingham Forest player in the upcoming hours, and Magpies boss Eddie Howe could make a late replacement for the midfielder.
The Magpies are also close to completing the signing of young full-back Harrison Ashby from West Ham.
David Moyes may also wish to bolster his squad after selling Craig Dawson to Wolves, following on from Issa Diop’s shift across London to Fulham in the summer, and were linked with Everton defender Michael Keane.
Fulham manager Marco Silva said over the weekend that he would like to make two additions to his squad before the window shuts.
Sasa Lukic the most likely to make the move to Craven Cottage, despite repeated interest from the club in Arsenal’s Cedric Soares.