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.