Radja Nainggolan, Roberto Gagliardini and Ionut Radu have all tested positive for coronavirus, Inter have announced.
The Nerazzurri issued a statement on Friday, eight days before they are due to face Serie A rivals Milan in the derby, revealing the trio were all shown to have contracted COVID-19.
Tests on the players were conducted at the club's Appiano Gentile training headquarters.
"FC Internazionale Milano announce that Roberto Gagliardini and Radja Nainggolan tested positive for COVID-19 following checks carried out at Appiano Gentile in recent days," Inter said.
"Ionut Radu also tested positive this morning [Friday], after tests carried out yesterday. Further checks are scheduled for tomorrow."
Midfielder Gagliardini started Inter's previous two Serie A fixtures, scoring one and assisting another in the 5-2 victory over Benevento on September 30.
Nainggolan returned to San Siro for this season after spending the previous campaign back on loan with Cagliari, though his only appearance of the campaign so far was a 15-minute cameo off the bench against Fiorentina.
Back-up goalkeeper Radu has never started a Serie A game for Inter and his only league appearance with the club came as a substitute back in 2016.