Speaking at Tuesday's Ireland team announcement, head coach Declan Kidney, Dowling's former provincial boss, confirmed that the Kilkenny man is facing a lay-off of 'a minimum eight weeks.'
"Unfortunately the word we've been given is that we won't be able to include Ian in our plans any time during the Six Nations," Kidney explained.
"He'll be treated at home. There are excellent medics in all the provinces and he'll get regular care and it's the consistency of that care that will bring him through rather than changing physios or medics in between (if he stayed with us in camp)."
Dowling had been named in the Ireland 'A' squad for Friday's encounter with England Saxons at Donnybrook but cried off along with injured hooker Bernard Jackman.