The Saints have been looking to bring in a new midfielder following the departure of Pierre-Emile Hojbjerg to league rivals Tottenham Hotspur earlier in the transfer window.
Southampton were linked with a move for Toulouse’s Ibrahim Sangare, but missed out on the signing after he joined PSV Eindhoven this week.
With time running out in the window, Ralph Hasenhuttl’s side then turned their attention to Ligue 1 side Brest’s 21-year-old midfielder Diallo.
According to French radio station RMC, Southampton have reached an agreement with Brest over a €15m deal to sign Diallo.
The France Under-21 international only moved to Brest from Monaco last year and could be on the move again, with England the destination this time.
Southampton have also been credited with an interest in Liverpool’s Marko Grujic and it remains to be seen if capturing Diallo will change that.
It remains to be seen when Diallo will land in England to put pen to paper on a contract with the St. Mary’s club.
