Birmingham boss Alex McLeish is hoping for a swift answer from Kenny Miller on whether he will join Blues.
Miller looked set to return to the Premier League after Birmingham had a bid accepted by Rangers on Friday.
But the move was put on hold after Italian club Fiorentina made an approach for the 31-year-old striker.
The former Wolves and Derby frontman is now weighing up his options and McLeish, who worked with Miller when in charge of Scotland, would like to know sooner rather than later if he wants to move to St Andrews.
"We have an agreement with Rangers and we are talking to Kenny," he said. "He's also got an offer from Italy.
"I know he is talking about coming back to the Premier League or possibly going to Italy so we will probably ask Kenny for a quick decision.
"I think he's had the offer from Fiorentina. I don't want to talk about Kenny's business but we made an offer, Rangers accepted it and we await Kenny's answer."
Miller returned to Scotland in the summer of 2008 after failing to help Derby beat the drop during the 2007/08 season.