The Leinster management counted the cost of Saturday night’s defeat to the Glasgow Warriors with Kevin McLaughlin and Dominic Ryan sustaining ankle injuries.
It is anticipated that neither forward will be available for selection this week.
The injuries could hardly have come at a worse time for Joe Schmidt and his staff who must already contend with the absence of 14 players on World Cup duty as well as longer-term absentees such as Mat Berquist, Andrew Conway, Shane Horgan, Tom Sexton and Eamonn Sheridan.
Berquist and Sheridan are expected to be unavailable until the New Year and Conway (ankle) should return over the coming weeks.
Meanwhile, hooker Sexton could be back over the next month after undergoing knee surgery over the summer months.
Luke Fitzgerald was withdrawn midway through the second half against Glasgow with cramp as a precaution and though he sat out training on Monday, Leinster are hopeful he will be available for selection.
Steven Sykes stepped up his rehabilitation and though he may again miss out on selection, he could be available for Leinster’s next home match a week later in the RDS against Aironi.
Ulster coach Brian McLaughlin may be without two key figures in his backline for Sunday’s game against the Ospreys.
Darren Cave (leg) and Ian Humphries (shoulder) are both doubts after picking up injuries last weekend and are due to get scans this week to determine the extent of the damage.
Despite this setback McLaughlin is confident his side can continue in winning ways.
"Ospreys have won all their games so far this season too so it will be another tough game for us,” he told UlsterRugby.com.
“If we play as well as we have been I see no reason why we can't get another win and that would put us in a really strong position.
“We lost by a point to them last season so there's no doubt it will be another big challenge for us."
In the Munster camp, the squad has emerged unscathed from their 35-12 win over the Scarlets in Musgrave Park last Saturday, boasting a clean bill of health ahead of Friday’s trip to the Cardiff Blues.
An added bonus is the inclusion of Danny Barnes and Ian Nagle in the 26 man squad named by Tony McGahan today.
Barnes missed last weekend's game with a minor hand injury but he and Nagle are fully fit with the lock recovering from a shoulder injury suffered against London Irish.
Tomas O'Leary is expected to do light training this week with a return to full training next week on the cards.
Peter Borlase (Achilles) remains unavailable for selection along with Troy Smith who had surgery last week on a cruciate ligament injury, while Felix Jones and David Wallace are only beginning their long road to recovery.
Munster: J Murphy, S Deasy, D Howlett, S Zebo, T Gleeson, D Barnes, L Mafi, D Hurley, I Keatley, D Williams, P Stringer, M Horan, S Archer, BJ Botha, W du Preez, J Hayes, D Fogarty, M Sherry, D Foley, I Nagle, M O'Driscoll, B Holland, P O'Mahony, N Ronan, J Coughlan, T O'Donnell.