Ireland have not ruled him and expect flanker Jordi Murphy to train on Thursday.
The Ulster back-row was forced off throughout the 35-0 win over Russia of Ireland using a rib injury, lasting 26 minutes of the success on Thursday.
The 28-year-old had just arrived in Japan to substitute Jack Conan, who had a foot.
Ireland chose not to substitute Murphy during the weekend and are now hopeful he will be ready for Saturdays Pool A decider at Fukuoka, where they need a bonus-point victory.
Hes a good deal better, a lot better than we thought hed be, stated damn trainer Andy Farrell.
Hes shaped up quite nicely. We expect Jordi to train on Thursday.
Weve been told he will be available to train on Thursday, so we select our staff in and about that.
We are happy with how Jordis pulled up. He was pretty sore. But following the medical information he has been given hes in good spirits.
Joey Carbery trained on Tuesday, having shaken off his ankle problems recurrence.
The Munster fly-half was because of cover but was a late withdrawal after aggravating the dilemma which had threatened his World Cup at the first place.
Carbery had conquered that complaint to be named in the initial 31-man squad and suffered ankle ligament damage in Irelands 29-10 victory over Italy in Dublin on August 10.
But the 23-year-old suffered a slight relapse to the Russia clash in the build-up , raising fears of his involvement.
He is flying, hes in a terrific location, said Farrell.
Hes in the best place Ive seen him over the last few weeks. He ran with a proper spring in his step. He is in good spirits and he is prepared to go.
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