Despite beginning the season as Alex's leading forward, Miller became a peripheral figure in their League Two promotion campaign due to the emergence of Nick Powell and Max Clayton, while Ajay Leitch-Smith led the line impressively.
Now boss Steve Davis concedes a move to pastures now for the 24-year-old may be the best solution for all parties.
"He has been at the club for a long time and has seen his progress halted this season," Davis told the Railwaymen's official website. "He has been in the shadow of AJ, Nick and Max for much of the season and he couldn't push beyond them.
"He may need a fresh start, a fresh spark to get himself going again and this is the way he may see it. He has a year left on his contract and at the moment we are not sure if he is going to be here or not.
"We will have to see what happens with him, but maybe having a fresh challenge is what he needs at this stage of his career."