Captain, Iain Henderson, suffered a concussion early in Saturday night's URC game against Connacht and will now follow World Rugby Graduated Return protocols.
Stewart Moore suffered a sterno-clavicular joint injury during the game and he too will be unavailable for selection this week.
Jude Postlethwaite (shoulder) and Ethan McIlroy (ankle) were also injured.
Their fitness for selection will be monitored through training this week.
Eric O'Sullivan has resumed full team training following a shoulder injury he sustained in training last week.
Stuart McCloskey (knee and ankle) has resumed team training and his availability for selection will also be monitored during the coming week.
Longer term injured players include Robert Baloucoune (hamstring), Rob Herring (calf), Tom Stewart (ankle), Jake Flannery (finger) and James Hume (knee).