Saido Berahino's eight-week Football Association ban was reportedly down to testing positive for Class A party drug MDMA in September.
News emerged on Thursday evening that the 23-year-old was handed the suspension during his time at West Bromwich Albion for use of recreational drugs.
West Brom boss Tony Pulis refused to go into any further detail when plugged on the issue during Friday's press conference, claiming that the problem was now down to Stoke City to sort out following Berahino's recent £12m move.
According to The Sun, the England international hopeful tested positive for MDMA - the substance found in ecstasy tablets - earlier this season, and did not feature for the Baggies between September 10 and his transfer to the bet635 Stadium last week.
Berahino is said to have explained his personal issues with the FA, claiming that he had suffered depression due to weight problems and had also turned to drink.
The Albion academy product made his debut as a second-half sub for Stoke against Everton in midweek.
