Rovers had an undisclosed bid for the Scotland international midfielder accepted at the weekend but have been unable to make much progress agreeing terms with the player.
The 23-year-old has one year left on his current contract and has been told he has no future at Aston Villa after falling out with manager Paul Lambert, who has told him to train away from the first team.
The Scotland international isn't keen on dropping down to the Championship and is thought to be stalling over talking to Blackburn in the hope a top-flight club will make a move for him.
Despite the delay in proceedings, Bowyer is remaining positive over Blackburn's chances of signing Bannan.
"We're exploring all options," Bowyer told BBC Radio Lancashire.
"There may be a chance it might happen, and if not we'll be prepared for it not happening. We've just got to keep as many plates spinning as we can."
Bowyer went on to say that he was confident there would be more new arrivals at Ewood Park before the first game of the Championship season on Sunday.