New Zealander lost high-profile bout in London
Fight could prove his last one for a lengthy period
Joseph Parker failed a drugs test on the day of his 11th-round stoppage to British heavyweight Fabio Wardley.
Ipswich-born Wardley and New Zealander Parker produced a pulsating encounter in London on 25 October to determine who would become WBO mandatory challenger to undisputed world heavyweight champion Oleksandr Usyk.
Parker had been next in line to face Usyk after putting together an impressive six-fight winning streak, but put his mandatory challenger status on the line in London and suffered an 11th-round stoppage in what could now prove his last fight for a lengthy period of time.
