Race against time to be fit for Six Nations
What is Cian Healy's injury?
Mercifully, it is not the same ankle he injured on the Lions tour. Players can regularly 'roll' an ankle. Normally, this causes just sprained ligaments and there is no lasting damage.
In some cases, as with Healy, the rotating force is more violent and the issue can be more significant and the sprain can affect ligaments and tissue that join the two shin bones -- the sydesmosis ligaments -- together.
Surgery is needed to insert a screw between shin bones to bind them together while the syndesmosis heals. Excessive walking early on can cause the screw to break, so normally the patient must stay off his feet for at least a month.
As Healy lamented via Twitter yesterday, he may have to park his beloved Jeep for a while as he gets used to walking in "moon boots" and wearing crutches. He has suggested a moped as an alternative. Clearly, we're no medical experts but that probably wouldn't be advisable!
When will he be back?
Healy will miss the festive derbies and the remainder of the Heineken Cup pool stages but Leinster hope he can return in time for either of their away Pro12 games against Cardiff or Treviso in late January.
Ireland will need to see him in action as the Six Nations kicks off on the first week of February.
Given that Healy's role of prop places a lot of extra pressure on his ankle, his recovery will be delicately observed.