Ireland hooker Rory Best will miss the entire season after picking up a neck injury.
The Ulster captain is set to undergo an operation to repair a chronic disk injury, with a likely recovery time of up to 12 months.
The loss of Best is a massive setback for the province and new coach Brian McLaughlin.
"This is a huge blow us. Rory is one of our most experienced players," said Operations Director David Humphreys.
"But what is most important is Rory's long-term health and welfare, and there is no reason not to expect him to return fully to rugby, after surgery and rehabilitation, next season.
"The timing of this injury presents difficulties as most players are contracted for the 2009-10 season.
"While we strengthened our hooking options this summer with the signing of Andy Kyriacou, we are working at present to find a replacement for Rory within world rugby."