Inter goalkeeper and captain Samir Handanovic, defenders Danilo D'Ambrosio and Stefan de Vrij, and midfielder Matias Vecino returned positive test results. D'Ambrosio's and Handanovic's positive tests were announced on Wednesday, with the results for De Vrij and Vecino arriving on Thursday.
Inter released a statement on Thursday explaining that suspension of first-team activities will last for four days leading up to and including Sunday, March 21. Local health authorities requested that the Sassuolo match be cancelled, with Serie A confirming the official postponement of the game.
As well as prohibiting Inter players from joining their countries' squads for the upcoming FIFA international break, the statement adds that new tests must be done before first-team activities can resume on Monday.
The ban on players leaving would mean Belgium's Romelu Lukaku and Denmark's Christian Eriksen must remain in Milan, as well as Italy players ahead of World Cup qualifying matches against Northern Ireland, Bulgaria and Lithuania.
It is the second time this season that Inter have suffered a coronavirus outbreak, with several first-team players testing positive in October.
Earlier this season, Juventus had been due to host Napoli, but the visitors were banned from travelling due to a coronavirus outbreak in the region. The league did not postpone the match and initially awarded the hosts the victory before a successful Napoli appeal saw the game rescheduled.
Inter are first in the Serie A table, with AC Milan nine points behind in second and Juventus a further point behind in third, though Andrea Pirlo's side has played one fewer game.