N’Golo Kante has suffered a setback in his recovery from a hamstring injury after returning to training last week.
Kante hasn’t featured for Chelsea since they faced Spurs at Stamford Bridge in August.
The midfielder was moving toward a return to first-team action but has been set back in his quest to play in the near future.
Speaking to reporters, Potter said: “N’Golo, we’re just waiting for his reaction from his training. It is certainly not ideal [his reaction] so we will have to wait and see the extent of it and go from there.
“It’s not ideal and it is disappointing for him and for us.”
Potter has a relatively strong squad still to chose from for the trip to Milan on Tuesday. Wesley Fofana picked up an injury in the fixture last week and Hakim Ziyech is ill so has not travelled to Italy.
The Blues will be hoping to repeat their impressive victory against the Rossoneri on Tuesday before they get back to Premier League action against Aston Villa on October 16.
