Barnsley manager Gerhard Struber has declined to comment on allegations that defender Bambo Diaby has failed a drugs test.
It was reported on Tuesday evening that the 22-year-old was tested following the Reds' defeat to Blackburn on November 23.
Struber said on Monday that Diaby was struggling with a knee problem as he missed Saturday's defeat to Bristol City and Tuesday's 3-0 loss against Preston North End.
"The situation is not clear, the process is running," said Struber.
"The information comes next week and we can tell more about Bambo then."
Diaby joined Barnsley from Belgian first division club Lokeren in July for an undisclosed fee.
He has played 22 games for the Tykes this term, with his last appearance coming in a 2-1 win over Huddersfield Town on January 11.
Barnsley visit Portsmouth in the FA Cup fourth round on Saturday and Struber said the defender is available for selection if he recovers from his knee complaint.
"He has an injury," Struber said.
"But I think it is not the right moment to speak about Bambo."