Bailly is a player Manchester United have been willing to let go since they brought in Lisandro Martinez from Ajax earlier this summer.
Several clubs in Europe such as Roma and AC Milan have shown an interest in getting their hands on the centre-back.
West Ham though are also keen on landing Bailly, with David Moyes wanting to reinforce his defensive options, and they have been heavily linked with moving for him.
But the Hammers are now set to face a battle if they want Bailly as Marseille have made a move to sign him.
The French giants are now in talks to take the Ivory Coast centre-back to the Orange Velodrome this summer.
Marseille are discussing potentially signing the defender on loan with an option to buy in the ongoing window.
They are in the Champions League this season and the French giants have the funds to secure a deal for the centre-back.
It remains to be seen whether West Ham table a concrete offer for Bailly from now until the end of the window.
