Stoke boss Mark Hughes has confirmed striker Saido Berahino served a suspension before he joined the club.
The Daily Mail has reported Berahino tested positive for a recreational drug during his time at West Brom.
Berahino signed for Stoke last month after completing the ban.
Hughes, speaking at a press conference covered by the club's website, www.stokecityfc.com, said: "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.
In terms of more detail you would probably need to refer back to his former club. We aren't in a position to give any more details as we don't have them.
"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."