Not only Icardi, Inter and Napoli are also fighting for Diakité. Di Marzio writes on his blog:

“The game between Inter and Napoli continues on the mercato. After Icardi the both clubs will fight for Diakité who has an expiring contract. Napoli has a slight advantage, but Inter are going to make a try. Both Liverpool and Rubin Kazan are interested as well, but the player wants to rest in Italy which makes it a fight between Inter and Napoli.”

Source: Fcinternews.it