Saido Berahino served an eight-week suspension after testing positive for a recreational drug during his time at West Bromwich Albion.

Mark Hughes, the Stoke City manager, confirmed on Friday that the player had served an eight-week ban before moving to the club from West Brom for £12m last month and it has subsequently been established by the Guardian that the sanction was handed down to Berahino from the Football Association on the back of a positive doping test.

“We are aware of it clearly – there was an FA disciplinary matter and Saido had an eight-week suspension, I believe. We were aware of that before we signed him,” Hughes said. “He had issues at his previous club for 18 months, which this is obviously a part of.

“As with all players we did our research on him before we signed him, but that didn’t change our thinking at all. We are pleased with what he is producing and he is looking forward to the game tomorrow.”

Tony Pulis, the West Brom manager, also confirmed the ban on Friday. “Saido served a ban while he was here but I won’t comment why. He didn’t play for me because he wasn’t fit enough,” he said.

The FA has declined to comment on the matter.

In November last year, Berahino admitted he had struggled for focus in the previous 12 months, describing himself as having been “in turmoil”. He said: “This last year has been the most difficult of my career and it has left me short of the form and fitness required for the Premier League.

“I have never been a player who lacked confidence or a belief in himself but that has been where I have found myself and it has hit me hard. It has left me feeling depressed and struggling for focus which has made it even more difficult to regain full fitness.”

Berahino did not play any competitive football between West Brom’s Premier League game at Bournemouth on 10 September and making his Stoke debut in the 1-1 draw with Everton on Wednesday. He could now make his second appearance for Stoke against his old club at the Hawthorns on Saturday.

“Why wouldn’t I play him? He is in line to be involved,” Hughes said. “He came on to good effect on Wednesday and there is no reason why he shouldn’t be involved tomorrow. He is itching to play a part, although the way the game is going will determine whether he comes on.

“Most opposition players get some stick, and he will get some I am sure, but he is of the view that he is probably used to having some stick from West Brom supporters.”