Ronan Loughney fractured an eye socket during last Friday's defeat at Murrayfield and the medical staff have confirmed that the Galway-born prop will be out of action for at least four weeks.
Also doubtful for this week is forward Aly Muldowney who suffered a shoulder injury on Friday night.
Try scorer Robbie Henshaw left the pitch in the second half at Murrayfield with an ankle injury. But the management are hopeful the 20-year-old will be available for his ninth European Cup appearance this Sunday.
Meanwhile, it has been confirmed that versatile back Danie Poolman will require knee surgery and is unfortunately facing up to three months on the sidelines.
Both Tiernan O'Halloran and Andrew Browne who featured for club side Buccanners in their win at the weekend sustained knocks and are unlikely to be available for this week's Heineken Cup game.
In the British & Irish Cup, Connacht Eagles welcome Bedford Blues to the Sportsground on Saturday afternoon. The round 3 fixture kicks off at 2.30pm and the team will also be announced on Friday.
Nigel Carolan's charges won their last pool game at home to Rotherham Titans (27-25). There will be free entry to the game for all Connacht Season Ticket holders.
Meanwhile, ticket sales for the Heineken Cup round 4 clash with Toulouse at the Sportsground a week later - Saturday, December 14 (kick-off 6pm) - continue to progress steadily.
The famous Clan Stand and Enclosed Area are sold out, but remaining tickets are on sale now online from tickets.ie, from the Connacht Rugby office or from Centra and SuperValu stores province-wide.