Balotelli seen pictured holding a shotgun
The AC Milan striker caused a stir with the photo captioned 'big kiss to all the haters' with the shotgun aimed at the camera, before removing the post off Instagram.
Milan vice president Adriano Galliani said he was helpless to sanction the Italy international.
"I have my own ideas about social networks and I've tried many times but our lawyer has always stopped me, saying that it would violate individual rights," Galliani said.
"In contracts it's written what players can and cannot do, but we can't do anything regarding their private lives. We do it vocally but that's not enough."
Balotelli, 23, scored once for Italy in their FIFA World Cup campaign in Brazil, as Cesare Prandelli's men bowed out in the group stages.
Some of Balotelli's prior controversies include throwing darts at youth squad members while at Manchester City in 2011, and setting off a firework in his own house later that year.