The 22-year-old Spanish centre-back has not played since January during an investigation into an alleged failed drugs test after Gerhard Struber’s first game at Blackburn Rovers in November.
The FA have refused to comment on the investigation or offer any guidance on when it will be finished.
Head coach Struber told the Chronicle: “Bambo Diaby is training with us but we have no information from the FA. I think, in the next few days, we will have information and a clear result. “But we will see.”