Leinster Rugby will not give anymore information on Sean O'Brien's injury setback until later in the week, after they receive a full medical report.

O'Brien suffered the problem during rehab on the hamstring injury which he sustained on Six Nations duty last February.

The Ireland and Leinster flanker has been blighted with hamstring problems for a long time now and missed the Championship opener against Wales due to a tightness in the muscle.

He returned to play against France but after just 20 minutes of action, the Tullow Tank went down in agony and has not been on the field of play since.

Blues head coach Leo Cullen set alarm bells ringing before the Guinness PRO12 win against Benetton Treviso.

"Seanie has that high hamstring tear which can be complicated. It wasn't a complete rupture like some of the other players have had. It is quite complicated. It is slower than we would have liked."

An update from Leinster defence coach Kurt McQuilkin did not offer any hope at today's media update at Blues HQ Cian Healy is not expected to feature in Friday's Guinness PRO12 semi-final, with the prop suffering from "general wear and tear" and he has been training away from the rest of the squad.

Rob Kearney (ankle) is "making good progress" while there was some good news on another batch of players.

Johnny Sexton (neck and shoulder) has been "flying around the place" according McQuilkin who confirmed that Luke Fitzgerald is back training after tweaking his medial ligament in the last meeting with Ulster.