The 24-year old striker departed the club for Blackburn Rovers in August 2011 but has failed to fire in England and has been linked with an Ewood Park departure this summer.
However, the Terrors were unsuccessful with an initial loan bid and McNamara does not know if there is any point returning with another offer for Goodwillie.
"We made an approach to Blackburn. They said it wasn't enough, so that's where we are at the moment," he told Sky Sports News HD.
"If we go back in, we'll see. We have got other targets we are trying to pursue and hopefully we can get the right ones in.
"I think he's a very good player but there has to be a line as well.
"It's a loan. It's different if you're buying someone and they are going to be an asset to your club.
"He's a fantastic player and I would like the chance to work with him, but he's not our player. You can only try. So far it's not been successful, but we have got other players there we can add as well."