The 25-year-old failed to impress last season after arriving at Anfield from the San Siro as a £16 million replacement for Luis Suarez, scoring just once in 16 Premier League appearances.
Balotelli rejoined Milan on a season-long loan deal over the summer, but has made just three Serie A appearances due to a recurring groin injury.
And Italian newspaper La Gazzetta dello Sport claims that the former Manchester City attacker will now undergo a hernia operation after meeting with Danish specialist Professor Pol Holmich.
As a result, Balotelli looks likely to spend another three months on the sidelines after making his last appearance in late September.
And the Italy international’s long-term future under Sinisa Mihajlovic now looks unclear as Milan aim to qualify for next season’s Champions League.
Despite the prowess of Carlos Bacca in attack, the Serie A giants are believed by the Daily Mail to be eyeing Paris Saint-Germain’s Zlatan Ibrahimovic, and Balotelli could miss out on a permanent deal if he fails to put his injury woes behind him.