Munster's preparations for tomorrow's epic Heineken Cup semi-final against Leinster have suffered a potentially crippling blow with the news that Peter Stringer picked up an injury during training yesterday.

The Ireland international is understood to have sustained a knock to the back of the knee and his involvement at Lansdowne Road is now in serious doubt.

Stringer, one of the mainstays for Munster with 110 caps to his name, has not been ruled out at this stage and will be afforded every opportunity by coach Declan Kidney.

However, it is clearly a major headache for Kidney and his backroom team who have already lost Marcus Horan this week along with long-term absentees Christian Cullen and Alan Quinlan.

Leinster, in contrast, are in rude health and coach Michael Cheika was able to name a full-strength side yesterday.