And now the European champions will have to make do without their No 9 against Norwich on Saturday and next week’s Carabao Cup tie with Southampton on Tuesday, 26 October.
“There’s no big news,” Tuchel said. “They will be out of Southampton too but from there we will see. They are both having treatment and feeling positive.”
While Tuchel added that the injury may work as a silver lining to Lukaku and ensure he has a rest.
“His body didn’t demand a break,” added the Blues boss. “It was not a muscle injury so I don’t understand that. It is just some percentage, please don’t underestimate the effort these players go through.
“We want him to be the top dog at Chelsea and at some point, you get tired. If you turn the wheel and turn the wheel and turn the wheel then you get tired.
“There is no major problem. Sometimes speaking about it helps.”
Joining the Belgian on the sidelines for Saturday’s game against Norwich will be Timo Werner.
The German also hobbled off midweek, while Christian Pulisic also remains out.