Leinster's new out-half signing, Mat Berquist, will be out of action for approximately four months.
The New Zealander sustained a fractured knee cap in the recent RaboDirect Pro12 win over the Dragons, and following an operation, it was announced that he will be sidelined until the New Year.
Berquist will miss Leinster's opening Heineken Cup games as the champions set out to retain the title they won in such dramatic fashion at the Millennium Stadium last season. Leinster face a demanding test in Round 1 with a trip to Stade de la Mosson where they meet tournament newcomers, Montpellier, on Saturday, 12 November.