Manchester City are still interested in luring the England midfielder away from Villa despite having an opening £20 million bid rejected.
And although Randy Lerner and Martin O'Neill are keen to retain Milner their resolve could be fiercely tested by an improved City offer.
"James Milner's a bright young lad and he's got a sensible head on his shoulders so I'm sure he'll do what's best for his career,'' Dublin told the Birmingham Mail.
"There's bound to be a lot of haggling between Villa and Manchester City and possibly a few other clubs.
"Villa will have their idea about what he's worth and City will have their idea about how much they are willing to pay.
"But at the end of the day it will be down to James to decide where he wants to play his football. If he thinks he's got more chance of achieving things away from Villa it will be hard to keep him. From what I hear he's the type of lad who won't rock the boat.
"But the way football is today, if a player is not happy at a club and wants to move somewhere else then that's usually what happens."