AC Milan striker Mario Balotelli has been ruled of contention for Italy's friendly against Argentina tomorrow night through injury.

Balotelli picked up a knee problem in training for the Azzurri on Monday, the latest problem in a summer full of injury niggles for the ex-Manchester City forward.

Italy team doctor Enrico Castellacci revealed that the forward is unlikely to be risked for the Rome friendly, ahead of Milan's Champions League qualifier against PSV Eindhoven next week.

Castellacci told reporters: "He has a slight swelling in the right knee, the one that underwent surgery and therefore every now and then swells up.

"There is some liquid in there, but nothing worrying. Whether he plays against Argentina depends on how the knee responds over the next couple of days."

Balotelli stayed with the Azzurri squad to meet Pope Francis earlier today, at a civic reception which saw both Italy and Argentina welcomed to the Vatican.