He has not been involved in full contact training with Toulon tests coming up
Leinster have revealed that Sean O'Brien has yet to return to full contract training as he struggles to overcome an inner ear problem.
The flanker paid a visit to a specialist today in an attempt to get to the bottom of the problem, which has limited him to non-contact training this week.
Leinster defence coach Kurt McQuilkin has admitted that it is unclear if O'Brien will recover in time to be involved in this Sunday's Champions Cup match-up against Toulon.
Scrum-half Luke McGrath and centre Noel Reid are both facing several weeks out of action with ligament damage.