Sydney - Former All Blacks star Sonny Bill Williams on Tuesday said his heavyweight boxing bout against South African Francois Botha was in doubt after picking up an injury playing rugby in Japan.
Williams, who in August quit the world champion New Zealand team to take up a club contract in Japan, injured his pectoral muscle playing for the Panasonic Wild Knights on Saturday.
He arrived in Sydney on Tuesday to prepare for the Botha fight next month but said he needed to have scans on the injury before deciding whether he went ahead with the bout.
"At the moment, it (the fight) is a little bit in doubt," Williams told Fox Sports at Sydney airport.
"I just came back here straight away.... I've got to get some scans and see how the pec is, see the extent of the injury."
Williams, the New Zealand heavyweight champion, is set to take on veteran Botha, 44, in Brisbane on November 24.
Williams, who is on a contract to play 12 matches for Panasonic worth a reported US$1.2 million, crunched his shoulder attempting a tackle on former Western Force centre Gene Fairbanks during Saturday's match.