Connacht scrum-half Frank Murphy will miss Saturday's Pro 12 match against Leinster in Galway after suffering concussion in the defeat to Munster.
The Cork man won his 100th cap for the province in the 22-16 loss at Thomond Park.
It is hopeful that fullback Gavin Duffy, who left the field during the second half last Friday, will recover in time for the derby.
Ahead of Friday's team announcement, the medical staff will continue to monitor the recovery of flanker Jake Heenan (shoulder). The 21-year-old was forced to sit out his first game of the season last week with his injury.
Pat Lam's squad has been boosted by the return from injury of forwards Michael Swift, Sean Henry and Ronan Loughney who all trained on Munday and will put their hands up for selection this week.
Meanwhile, outhalf Craig Ronaldson (hamstring) faces at least another two weeks on the side-lines while centre Dave McSharry (ankle) will be out of action until after the well-earned January break at the end of the month.