The 24-year-old picked up an injury in training while he was away on international duty.
He had to overlook the European Qualifier against Scotland and of Belgium – having made a promising start to his Premier League career – he is absent until after the next round of qualifiers in mid-October.
Brighton manager Graham Potter said:”It’s early stages with Leandro but he’s felt something in his butt.
“We don’t think that it is just as bad as initially believed.
“He’s clearly not likely to be accessible for the weekend and the other side of the next global fracture is probably what we’re planning for today.
“At the early stage, it’s tough to put too much more of a timescale on it.”
Brighton signed Trossard in the summer from Genk last month and he started his account for the club in a 1-1 draw against West Ham.
He has to make his international debut but was named in the group four times.
Brighton return to Premier League action at home to Burnley and they have matches from Chelsea, Newcastle and Spurs before the next round of action.
Read more:
