The Latics failed with a bid to sign the Australian on a season-long loan last month.
“There were many players we showed interest in and Scott McDonald was one of them,” Martinez told the Wigan Evening Post.
“I wanted to add to the squad with a couple of signings as we are a bit thin on numbers.
“We have our targets and we will carry on following and assessing them because if you are going to do that then I think it is vitally important that assessment continues.
“When you bring a player in you have to be certain that he brings you exactly what you want in terms of his personality, character and what he has to offer.
“I will continue to work hard to identify the right players to improve our squad.”