The 33-year-old is a long-time target for Martinez, although he has been featuring for the Rams in the Premier League this term and will take some persuading to drop down to League One.
"These things are not as easy as they look, and you have to remember that Darren Moore has played Premiership football this season and has a Premiership contract," Martinez told the Evening Post.
"It's going to be hard for him to drop to League One, but in football personal situations change from day to day.
"I am sure Billy Davies at Derby would love to hang on to Darren Moore for as long as he can because he is a leader and you need people like that when things aren't going your way, so we will just have to sit tight.
"When you consider we have lost Izzy Iriekpen and Steve Watt, centre-half is probably the only position where we haven't got that strength in depth.
"But as I have said all along, we will only bring someone in if it is the right player."