Diop appears to be one of the most highly sought-after defenders in Europe right now, with the Daily Mail recently reporting that the Hammers are joined by the likes of Tottenham, Arsenal and Barcelona in the race to sign the youngster.
And it appears that the Irons have looked to steal a march on their rivals, with The Sun (12/06; page 53) reporting that Manuel Pellegrini's men have now made a £25 million bid for the France under-21 international.
While The Sun does not suggest if Toulouse have responded to the bid or not, the Daily Mail recently suggested that the Ligue 1 side were keen to receive £26 million before they sanctioned a sale, so it would appear that the Hammers may be in the ball park required to make something happen.
It would be a boost for Pellegrini if he managed to sign Diop this summer as he appears to have an enormous of potential in a position that West Ham certainly need to add depth to during the coming months.
The Hammers struggled to keep the goals out this past season - no team in the Premier League conceded more often than they did - so bringing Diop to the London Stadium could be a massive statement of intent when you consider the sides also reportedly interested in his signature.