Robbie Henshaw a doubt for Ireland

Robbie Henshaw remains a doubt for Ireland's second World Cup clash against Romania at Wembley on Sunday.

Irish skills coach Richie Murphy admitted Ireland are "not quite sure" whether the Connacht centre will be ready in time for the weekend Pool D contest with Henshaw unable to take part in a full training session on Wednesday.

Johnny Sexton, Peter O'Mahony and Iain Henderson all sat out Ireland's session at St George's Park, but only as a precaution - all remain available for selection for Sunday's Romania clash.

"Robbie trained reasonably hard today, he did a lot of running and a lot of passing," said Ireland assistant coach Murphy.

"Again he's in a position where he's returning to full fitness and he's very close.

"Whether Robbie will be ready for this week we're not quite sure at this moment, but we're hoping that he will.

"He trained quite a lot today and he'll probably have to train back with the team in our next training session, which is on Friday."

Fly-half Sexton was substituted after only 55 minutes during Ireland's 50-7 rout over Canada in Cardiff last weekend, but Murphy insisted that had nothing to do with a slight knock to his knee.

"It's nothing serious with Johnny he picked up a bit of a knock to his knee during the game and we just felt it was right to let him sit out training today," said Murphy.

"He's fine. Everyone's in contention for Sunday, he's definitely not ruled out for any reason.

"Today is quite a long way away from the game so we felt it right to give those lads some time off today so they will be ready for the weekend."

Ireland boss Joe Schmidt is known to be keen on ensuring Henshaw and Jared Payne have ample time to be reacquainted in midfield as soon as possible, but Murphy insisted there is no rush to pitch the first-choice centre partnership back together.

"Those combinations, you want to try to build them, but those guys know each other pretty well now," said Murphy.

"I know they haven't played an awful lot together, but their understanding of each other has been pretty good up until now.

"So if they get the opportunity to play together this week that will build on that, but if not we don't see it as a major problem going forward."