Cian Healy is facing a "substantial" injury lay-off.
At a press briefing in the RDS this afternoon, Leinster head coach Matt O’Connor confirmed Healy was injured in training yesterday.
The Guinness Pro 12 Champions welcome Cardiff to the RDS tomorrow evening.
It’s not yet known how long Healy would be missing for – however he will miss next week’s inter-pro derby against Munster at the Aviva Stadium and their European Champions Cup opener against Wasps on October 19.
O’Connor said he will be closely monitored.
“Cian unfortunately strained his hamstring in training yesterday, it was nothing in it but he’s looking like a significant lay-off but Jack’s injury is minor and should be in the mix next week.”
“We just need to wait to get more information from the specialist and should have more later today.”
“It could be longer (than three or four weeks) we will have to see, it was a significant tear in his hamstring so we will have to see.”
Jack McGrath, meanwhile, should be available next week after pulling up with a calf injury in the loss to Connacht last weekend.