Kobe - Ireland are determined that Jordi Murphy will be given the "best chance" to overcome a rib injury and remain at the Rugby World Cup.

The unfortunate Ulster back-row forward lasted just 26 minutes of Thursday's error-strewn, 35-0 pool win over Russia, having only arrived in Japan a few days earlier to replace the injured Jack Conan.

"He's going to get scanned today, and (that will) give an exact detail on what's happened," Ireland scrum coach Greg Feek, speaking to reporters on Friday, said of Murphy.

"We know it's the ribs but that will determine once we get that back what his plan will be.

"The cartilage normally pops out, sometimes that can pop back in but that can be tender for a while... I think we'll give him the best chance to get it right."

Ireland captain Rory Best added: "You don't like to see anyone going home, like happened with Jack last week."

Ireland also have concerns over utility back Joey Carbery, a late withdrawal from his bench role on Thursday, because of ankle trouble.

Meanwhile star fly-half Jonathan Sexton, who returned to action on Thursday when captaining his country for the first time, played just 40 minutes before he was seen icing his leg after coming back from a thigh injury.

But after the match, Ireland head coach Joe Schmidt said: "Johnny's all good."

Fullback Rob Kearney, who failed a head injury assessment during last week's shock 19-12 defeat by Japan -- a match Sexton missed -- was also substituted after 49 minutes.

"Rob is okay. We were going to give him 50 or 60 (minutes). He felt a little bit tight in the groin and we felt it was about time to take him off anyway," explained Schmidt.

Ireland are still without star centre Robbie Henshaw since the beginning of the tournament with hamstring trouble and Chris Farrell is also sidelined with concussion.

The Irish do have a relatively long break, however, until their final Pool A game, against Samoa in Fukuoka on Saturday, October 12, where a victory over the Pacific islanders will secure a place in the quarter-finals.

They are still smarting from their loss to Japan. Nevertheless, having launched their campaign with a 27-3 win over Scotland and then securing a losing bonus point against Japan, Ireland's last-eight hopes remain in their own hands.