The Munster wing, Doug Howlett, will miss the rest of the season due to a ruptured Achilles tendon.
The former All Black will undergo an operation to repair the injury and a lengthy period of rehab means that the 33-year-old will play no part in the remainder of Munster's Heineken Cup campaign.
The 2006 and 2008 champions go into the critical back-to-back round 3 and round 4 games against the Scarlets fresh from two dramatic last-gasp victories over Northampton Saints and Castres.
The first contest between the two unbeaten clubs in Pool 1 gets under way at Parc y Scarlets on Saturday. (kick-off: 3.40pm)