Ireland coach Declan Kidney is considering his front row options against Australia after Marcus Horan was ruled out of action until the New Year.

Horan will be unavailable for up to eight weeks after undergoing an unspecified "routine medical procedure". Fears the 32-year-old's career is over have been dismissed, but Ireland are refusing to reveal any details about his condition.

His absence paves the way for either Tom Court of Ulster or Leinster's Cian Healy to stake their claim at loosehead for the autumn series against Australia, Fiji and South Africa.

Healy will have the edge on Court in the race to partner John Hayes, who is available to play again on Sunday upon completion of his five-week ban for stamping.

Horan's absence forced his omission from the 31-man senior squad named for the opener against Australia next weekend.

A statement released by Ireland read: "It has been confirmed that Marcus will not be available for the Guinness Series games.

"Following further tests this week, Horan underwent a routine medical procedure and will undergo a period of rest over the next number of weeks.

"It is expected that he will be available to Munster and Ireland after the New Year."

But there was more positive news over Horan's Munster team-mate Jerry Flannery, who has been included after showing encouraging progress in his recovery from a calf injury.