The former Manchester United striker is responsible for over 30% of the team's goals so far this season, but Antonio Conte will need to rely on someone else to hit the back of the net against Parma.
On Tuesday, Inter drew 0-0 away at Shakhtar, but arguably more damaging than the points dropped was the injury suffered by Lukaku, who could miss next week's Real Madrid clash also.
With Alexis Sanchez not fully fit either, it could present the opportunity for Conte to start highly-rated youngster Andrea Pinamonti, who would partner Lautaro Martinez up top.
Milan Skriniar is still not available as he continues his battle for fitness during coronavirus quarantine.
Stefan de Vrij, Alessandro Bastoni, and Danilo D'Ambrosio secured the clean sheet away in Europe, so could be trusted in the three-man backline again.
In midfield, Inter are without Matias Vecino and Stefano Sensi.
Roberto Gagliardini is available after being in quarantine.