Stefan de Vrij limped off with a muscular issue in the opening minutes against Napoli, as Inter are heading for an injury crisis in defence.
The Dutch international went down after 17 minutes at the Stadio Diego Armando Maradona this evening.
He limped off clutching the top of his thigh, with DAZN reporting he told the staff on the bench that it was a strain in the adductor.
This is turning into a real problem for Simone Inzaghi, because Alessandro Bastoni and Benjamin Pavard are already out of action.
It saw him introduce Carlos Augusto, the wing-back moved unusually into the back three as a central defender.
Now it remains to be seen how long De Vrij will be out for and if he managed to stop before doing any serious damage.
There is at least a week before the next fixture, with Bastoni hoping to make his return fairly soon.
Pavard is a long-term absentee after dislocating his kneecap.