Ireland wing Keith Earls could be ruled out for entire autumn series
Keith Earls could miss Ireland's entire autumn campaign due to a hamstring injury.
Munster wing Earls suffered the blow in training on Tuesday and has been ruled out of Saturday's November series opener against South Africa in Dublin.
Andrew Conway has stepped up to start in Earls' place to face the Springboks, with Darren Sweetnam primed for his Test debut off the bench.
New Zealand-born Bundee Aki will also make his Ireland bow this weekend, forging a formidable centre pairing with Robbie Henshaw.
"Keith picked up the injury on Tuesday, and it was a surprise to him and us," said Ireland head coach Joe Schmidt.
"It's a hamstring injury, and I think it's going to make it certainly a struggle for next week, and potentially the week after.
"So he will be a doubt for the series at this point.
"We're disappointed and so is he; he was sensational for us in Japan in the summer.
"Not only his on-field actions but the way he led the young players, that was a another role he had fully embraced in this camp.
"He's the consummate professional, a class player, that rapid acceleration.
"But what a fantastic chance for Andrew Conway and Darren Sweetnam."
Ulster wing Jacob Stockdale will start on the wing this weekend, with Cian Healy starting at loosehead prop as Jack McGrath continues to shake off a hip problem.
Connacht centre Aki has qualified for Ireland after completing the three-year residency period, having moved to Galway in 2014 from Super Rugby outfit the Chiefs.
The powerful centre with Samoan parents has come under fire in some quarters this week over his decision to chase Test representation with Ireland - but now head coach Schmidt has hit back.
"It's never irrelevant," said Schmidt of Aki's background.
"But sometimes where you're born is less relevant than where you're invested over the last period of time.
"I think Bundee has invested incredibly well in the west.
"They have benefited from his commitment, his ability and his durability.
"It's sometimes an unfortunate distraction, I do feel a little bit of sympathy for Bundee himself.
"He's just doing what he loves doing, and what he's good at.
"We just hope it doesn't distract him.
"There's no doubt in the players' minds, that they are excited to have him in the group.
"I think Bundee's combination with Robbie (Henshaw) has been something we've noticed in training when he's gone in and out.
"He brings a calmness actually, he has some really good experience in some pretty high-level games.
"He's very experienced playing against the southern teams, I know Jared Payne made his debut against SA in a similar sort of situation.
"That familiarity probably gives us a little bit more confidence in knowing what, when and how things are likely to occur."