Japan star gets the all clear
The 25-year-old Tonga-born player – who Japan coach Eddie Jones has praised as an unbelievable player – had feared a recurrence of a dislocated hip when he was stretchered off in the second half of Japan's game with Scotland on Wednesday.
His exit pre-empted a Japan collapse.
They conceded 33 points after he left the field to lose 45-10, paying the price for their stunning efforts in beating South Africa 34-32 last Saturday.
Mafi, who scored a first half try against the Scots to keep his side in touch, has yet to resume training.
Japan play Samoa on October 3 in Milton Keynes.
They will take comfort in the knowledge that the Samoans face the Springboks in what is likely to be a bruising encounter on Saturday in Birmingham.
Scotland, who play the United States on Sunday, top the table on five points, one ahead of both Samoa and Japan with the Springboks on two and the USA on zero, though the Japanese are the only ones to have played two games.
Source: Agence France-Presse