Why was Icardi excluded from the squad to play Lazio?

Luciano Spalletti, manager of Inter Milan, left Mauro Icardi out of his squad to play Lazio. The absence of the clubs's former captain surprised many because he had returned to training with the team. 

And, according to 'Gazzetta dello Sport', this could be due to a fresh conflict in the Inter Milan dressing room. 

Spalletti reportedly gathered his players and asked Icardi if he had anything to say to his teammates. 

"I have spoken with them and with the club, I don't have to do anything else", he replied, refusing to give any further explanations. 

As a punishment for this, Spalletti has left him out of the squad to play Lazio, and it remains to be seen when Icardi will make his long-awaited return to action.