The midfielder went off during the opening minutes of a 1-0 friendly victory over Olympique Marseille on Wednesday night.
Tests have now shown the lesion of the anterior cruciate ligament in his right knee.
Galloppa will undergo surgery performed by Professor Paolo Adravanti “at a date to be decided.”
This sort of injury generally requires four to six months on the sidelines.
The 28-year-old has two senior caps for Italy, but has a history of injury problems.
Galloppa also had surgery for two different cruciate ligament problems in August 2010 and October 2011, but those were both in his left knee.
Read the original article on FootballItalia