Matthew Dalton sustained a knee injury in the URC Round 6 clash with Benetton Treviso and will be unavailable for selection this week.
Iain Henderson experienced a back spasm during the warm-up before the same fixture, and his availability for Friday’s game will be assessed throughout the week.
There are further injury concerns for Cormac Izuchukwu (foot) and Rob Herring (ankle), both of whom will continue to be monitored during training.
Instonians full-back Bradley McNamara has joined the senior squad as short-term injury cover.