Ireland hooker Rory Best has been ruled out of Saturday’s Test against South Africa with a calf injury.
The Ulsterman went through “modified work” in training this week but he has failed to recover in time for the visit of the Springboks to Dublin.
An IRFU statement read: "Following a medical review on Tuesday evening Rory has been ruled out of selection for the game against South Africa.
"His calf strain that has been slower to heal than expected. He is partaking in modified training but a decision has been made not to risk him this weekend and his progress will continue to be monitored."
Best’s absence adds to Ireland’s front-row problems, with props Cian Healy, Marty Moore and Nathan White already ruled out, while Mike Ross is still fighting for fitness after groin trouble.
Sean Cronin is the frontrunner to replace Best at hooker. The 28-year-old has been in impressive form for Leinster this season, starting seven of their nine games.
Ireland will name their team to face South Africa on Thursday afternoon.
Watch Ireland v South Africa live on Sky Sports 2 on Saturday from 5pm