"We are not in a position where we have to sell," said Martinez, who is supposedly lining up Swansea's Leon Britton as a potential replacement for Scharner.
"I am looking to bring players in during January and I am sure we will do that but the focus just now is getting the best from players we already have.
"You won't hear me rejecting speculation about anyone coming to Wigan because we are having to look in a lot of leagues to find the right characters. For us, it is not just about signing good players, it is about making sure the personalities are perfect too."
On Figueroa, he added: "He is the kind of player we want to keep, of course. Obviously we don't want to lose our best performers and Maynor has been outstanding the whole season. And it is not just that, he is a terrific character.
"I would be very surprised if teams didn't want him because he is ready for big things.
"We know that we will not be able to keep him forever because the reality is he is slowly fulfilling his potential, and his potential should be to go to the top of the top.
"(But) he is a young man and he has enough time to get to the highest level. For now he is staying here."
Figueroa's stunning strike on Saturday was only his second goal in English football.
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