The 25-year-old Italian centre-half will consult a specialist later this week after scans revealed the full extent of his hamstring problem.
Bellusci was one of six first-team players controversially missing from head coach Neil Redfearn’s squad for Saturday’s defeat at Charlton.
Mirco Antenucci, Dario Del Fabro, Marco Silvestri, Souleymane Doukara and Edgar Cani also withdrew from the squad on the eve of the trip to The Valley citing injuries, prompting some accusations that the players had gone ‘on strike’.
Bellusci has made a total of 30 appearances during his debut season in English football, scoring two goals, after being signed in the summer from Catania.
He missed the Easter Monday defeat at Wolves and was an unused against Cardiff the following week.