The 24-year old striker left Tannadice for Blackburn Rovers in 2011 but has failed miserably in England, scoring five goals in 34 appearances in all competitions for the Lancashire club.
Goodwillie also had an ill-fated loan with Crystal Palace but is being tracked by McNamara who would welcome him back to United.
"Goodwillie definitely interests us. I think there are a few clubs after him but we have spoken to Blackburn," he told the Daily Record.
"He'd enhance the squad. The fans adore him from his time here and it would be great to have someone like that to work with."