Stoke City manager Mark Hughes has confirmed Saido Berahino served an eight-week ban over an "FA disciplinary issue" towards the end of his time at West Brom, amid reports the striker tested positive for a recreational substance.
Berahino left The Hawthorns to join Stoke for a reported £12million during the January transfer window, having played his last game for the Baggies on September 10.
The 23-year-old was said to have been sent to a fitness camp in France by West Brom boss Tony Pulis in the intervening period after struggling with his weight.
However, a report in the Daily Mail claims Berahino's absence from both the senior and Under-23 sides was down to a Football Association (FA) suspension following a failed an out-of-competition test.
Hughes confirmed his knowledge of the ban but did not elaborate on the circumstances.
"We are aware of it clearly - there was an FA disciplinary matter and Saido had an eight-week suspension," Hughes told a news conference ahead of a meeting between the two clubs on Saturday. "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."
West Brom boss Tony Pulis offered little more detail, commenting: "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.
"Saido is no longer an Albion player. He is at a club which I used to manage and I have respect for. It's one for Stoke to handle.
"This football club looked after Saido very well while he was here. The club looks after all the players."
The FA declined to comment on the case when contacted by Omnisport.