He said: "Obviously it is not ideal moving across town to play for another club. But it would not have bothered me that much. As a player you have to do what is right.
"If I felt it was the right move, I would have gone to Birmingham but I thought Bolton was the correct path to take. It was a hard decision to move away from the midlands as I had been at Villa since I was 13."
The prospect of European football, however brief, appeals to Cahill.
He said: "There is a lot of quality at this club. You do not get into the UEFA Cup with average players. It is brilliant to be at this level as you want to be competing with the top players. You get an indication then of where you are at in your career."