Joseph Parker tested positive during a anti-doping examination carried out the same day he fought in 11th-round loss to UK boxer Ipswich-born Wardley.
Fabio Wardley along with Joseph Parker were part of a thrilling encounter staged in the UK capital last October to decide the identity of the WBO mandatory challenger facing unified heavyweight titleholder Ukrainian champion Usyk.
Parker had positioned himself as next in line to face the champion after compiling a notable six wins in a row, yet placed his mandatory challenger status on the line in London and experienced a stoppage in round eleven.
A standard screening administered to the boxer through Vada the day of the match came back positive and now leaves the veteran boxer facing a challenge to demonstrate his cleanliness.
Parker's promotional company published a statement declaring: "The anti-doping body informed all required parties regarding Joseph Parker had a positive result subsequent to a doping test administered on the fight day. As the investigation continues, no additional comment will be made for now."
Parker became world champion six years ago prior to he surrendered his championship belt via unanimous decision versus Anthony Joshua in Cardiff 24 months later.
The fighter has been a frequent visitor across the United Kingdom since then, having eight matches altogether in the UK and relocating to Ireland for fight camps with highly regarded trainer former champion Lee over the past few years.
Guided by Lee, the boxer bounced back from the 2022 setback to Joe Joyce to chalk up several successes that placed him as the top contender to face Usyk until he lost against Wardley.
Following the boxer produced an adverse finding when he fought Wardley, reportedly involving cocaine, an investigation into the findings has been started.
