James Ryan is rated doubtful for Ireland's Six Nations clash with France on Sunday, with Rhys Ruddock on standby to play at Test level for the first time since the World Cup.
Ryan did not return after a HIA in last Sunday's loss to Wales and skipper Johnny Sexton, who had a HIA after the game, is also not guaranteed a place in the side that Andy Farrell names this morning, with Billy Burns a potential starter in his place.
At the start of the week, Tadhg Beirne would have been the front-runner to replace Peter O'Mahony in the back row with Iain Henderson, who had a big impact as Ryan's 23rd minute replacement in Cardiff, coming into the second row.
But now Beirne looks set to partner Henderson in that second row, with the in-form Ruddock able to fill the no 6 or no 8 jersey, depending on where Farrell wants to play CJ Stander.
James Lowe describes prolific French winger Teddy Thomas as "electric" - but the Racing flyer is in line to lose his place as Fabien Galthie looks to counter Ireland's aerial threat on Sunday.
Thomas scored again in Les Bleus' 50-10 rout of Italy in their Six Nations opener last week but Damian Penaud is seen as a safer bet under the high ball bombardment that France expect is coming in Dublin.
In the pack, Dylan Cretin's place is expected to go to Anthony Jeloch, who is seen as a better bet to counter Beirne's ruck threat as Ireland improved their breakdown work hugely in Sunday's loss to Wales.
"We've got our hands full this week," said Lowe, who along with Keith Earls will hope to start on the wing again, although Jordan Larmour is pushing hard for a recall.
"It's expansive footy, isn't it (from France). Man, they've got some terrific athletes.
"Antoine Dupont at No 9, Teddy Thomas on the wing.
"The fellah on the other wing (Gabin Villiere), he's half the size of me and he's hitting people bigger than me, getting turnovers at the ruck, it's quite scary to see! Y
"You don't normally see that, especially where I try and hang out.
"Dupont's an amazing player. To me, the world's best player at the moment.
"Aaron Smith actually just said he's watching Dupont, what's he's done for Toulouse and this French side.
"He's the key man and someone that we have to try to limit his damage. He's the one we're going for.
"They played very, very well against Italy, scored some amazing tries and defended very, very well.
"A lot of line speed so we'll try and implement that throughout the week and we'll put our best foot forward and try to knock them over".
