Connacht back row forward Eoin McKeon is a major doubt to play against Ulster in the Guinness PRO12 League match at Kingspan Stadium on St Stephen's Day.
The number eight-turned-flanker endured a ligament sprain to his knee against Leinster and must be considered an outside shot, at best, to take part in the Interprovincial.
Second row Andrew Browne has overcome a period of rehabilitation from the knee injury that has kept him out of the game for three weeks.
Former Ireland Under-20 wing Tiernan O'Halloran underwent a scope to examine his knee and the 23 year-old is expected to be free to play again in 3-4 weeks.
Former Leinster wing Fionn Carr is slowly, surely making his way back from the concussion that knocked him out of the contest against Bayonne in The Challenge Cup the week before last.
The close surveillance of return-to-play protocols means he will not be available for Friday night.