Ireland will hand Jordi Murphy the "best chance" to shake off his rib injury and stay at the World Cup.
The luckless Ulster back-rower lasted just 26 minutes of Thursday's 35-0 win over Russia, and that after jetting into Japan in midweek to replace the injured Jack Conan.
Ireland could call up Munster's Tommy O'Donnell or even Leinster lock Devin Toner as a replacement should Murphy's injury prove too serious for him to remain with the squad.
"He's going to get scanned today, and give an exact detail on what's happened," said Ireland scrum coach Feek, 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.
"These things can settle down. Sometimes the spot on the body can make it better or worse.
"I think we'll give him the best chance to get it right.
"With the weekend off, a decent turnaround to the next game, we'll assess him and go from there."
Ireland can seal their quarter-final qualification with victory over Samoa in Fukuoka on Saturday, October 12, but are still shaking off the after-effects of their shock 19-12 loss to Japan.
Ireland got the job done with a stuttering bonus-point win over Russia, the tournament's lowest-ranked team, but were again left frustrated with their performance levels.
Ulster stalwart and Ireland captain Rory Best admitted boss Joe Schmidt's squad now have everything crossed that Murphy can shake off his rib problem and stay at the World Cup.
"You don't like to see anyone going home, like happened with Jack last week," said Ireland skipper Best, of Murphy's situation.
"You understand it's part and parcel of rugby, especially at World Cups, because you've only 31 players you can't afford to hang on to somebody and hope they will be alright in a week or two because you don't have the luxury of time.
"So I think from our point of view Jordi's a great guy to have out here, he's very popular among the squad and a fantastic player.
"So for us we want to keep all our best players out here, and it would be a real shame if something happened.
"But we can only take it as what it is. A rib is something that sometimes looks a lot worse and lot more painful coming off the pitch than it actually is. And hopefully that will settle down pretty quickly."
Joey Carbery suffered a recurrence of the ankle injury that threatened his World Cup participation in the first place in training on Wednesday, and was a late withdrawal from the Russia match.
And Feek admitted Ireland have to hang fire on the extent of his injury problem now too.
Asked for an update on Carbery, Feek said: "We'll wait and see and see how it goes.
"It was more precautionary than anything.
"There are a few unlucky instances in rugby where you might get a little stamp.
"So rather than take a risk you minimise that.
"And to be fair to Luke McGrath he got through the 80 minutes well.
"I think if you look at all the teams there's been a few, a lot of high-speed running, a lot of tries being scored, the surfaces are firm and the players are trying to do the best they can.
"I'm not surprised, I don't think it's been too bad."
