Financial problems led to coach Antonio Conte's departure and the sale of star players Romelu Lukaku and Achraf Hakimi, but they played as though their troubles were behind them under new boss Inzaghi.
The diagnosis means the 34-year-old will miss Thursday's World Cup qualifier between Chile and Argentina.
"Arturo Vidal will undergo surgery tomorrow (Friday) for meniscal pain in his left knee," Inter Milan said in a brief statement.
Inter are equal on 40 points with local rivals Milan, who travel to Cagliari on Monday, with Juventus seven points behind the top two in fifth.
Coppa Italia: Romelu Lukaku's late winner sees Inter beat Fiorentina to set up quarter-final clash against Milan
Inter will be the home side when it plays its city rival at the end of the month. The two Milan teams are also leading Serie A with the Rossoneri top of the league, three points ahead of second-place Inter.
Second-placed Inter stay one point behind Serie A leaders AC Milan who host champions Juventus later on Wednesday.
LaLiga: Barcelona's salary cap for 2020-21 season slashed by $350 million amidst ongoing COVID-19 pandemic
The coronavirus pandemic has had huge economic effects on Spain's top-flight teams, with Barca among those worst affected.
"There are no negotiations with Manchester United," said Barcelona sporting director Ramon Planes. "Dembele is a player we are counting on."
'Nothing surprises me anymore', Lionel Messi bids farewell to Luis Suarez with fresh dig at Barcelona management
Messi has a long-running feud with club president Josep Maria Bartomeu which intensified after Barcelona were humiliated 8-2 by Bayern in a Champions League quarter-final in August.
After joining Barcelona in 2018, Vidal played 96 games for the Catalans and scored 11 goals, helping them win LaLiga in his first year in Spain.
Lionel Messi scores two in Barcelona's friendly game against Girona, Luis Suarez, Arturo Vidal remain absent
Lionel Messi netted two goals and set up one more in a 3-1 victory over second-tier Girona, Barcelona’s second training match since Ronald Koeman took over as coach.
Without directly accusing Bartomeu, Messi has been outspoken against the club’s decisions this season, the team’s first without a title since 2007-08.
Suarez and other players' departures would be part of the “profound” changes to the first team that the club announced after its season ended with a humiliating 8-2 loss to Bayern Munich in the quarterfinals of the Champions League.
Champions League: Arturo Vidal declares Barcelona 'best team in the world' ahead of Bayern Munich test
Vidal spent three years at Bayern, who are deemed heavy favourites to reach the semis after winning the German title and hammering Chelsea, while Barca crumbled in LaLiga.
Champions League: Barcelona's Quique Setien relying on Riqui Puig, Ansu Fati in absence of experienced stars
“Both Riqui and Ansu are ready to play,” Setien said Friday. “They have performed and played pretty well and could perfectly well start. And if they do start, I am sure they will be guaranteed to play well.”
LaLiga: Arturo Vidal’s lawsuit against Barcelona over bonus payments dispute won't affect status in team, coach Ernesto Valverde
Arturo Vidal's lawyers have filed a complaint to Spain’s player’s union (AFE) citing an unpaid bonus of 2.4 million euros (2.05 million pounds).
LaLiga: Arturo Vidal casts cloud on Barcelona's fixture against Espanyol after filing complaint over non-payment on bonuses
The lawyers working for Vidal filed a complaint to Spain’s player’s union (AFE) last month citing an unpaid bonus of 2.4 million euros ($2.69 million), news of which emerged while the player was back in his homeland during the league’s winter break
LaLiga: Lionel Messi, Luis Suarez and Antoine Griezmann find the target as Barcelona end year top of the league
Lionel Messi closed the year with a total of 50 goals for club and country for the sixth straight time, helping Barcelona stay top of the league entering the holiday break.
Real Madrid stay in touch with leaders Barcelona, who also have 28 points after 13 games but top the standings due to their superior goal difference.
Barcelona are back in form and LaLiga's big three are back at the top of the table after the defending champions put on a finishing masterclass to thrash Sevilla 4-0 on Sunday.