Both players were sent out on loan during the January transfer window - De Ridder to Hapoel Tel Aviv of Israel and Kapo to French Ligue 1 outfit Boulogne.
Martinez told the Wigan Evening Post: "I have not had a chance to speak to Olivier or Danny since the end of the season, and it's important we try to find a solution that suits all parties.
"Olivier played a lot of games for Boulogne in France. They got relegated but he was still playing at a high level.
"Danny had an injury but played quite a few games as well for Hapoel, so both players had successful spells with their loan clubs.
"It's important I talk to them to see how they feel and how the experience went. We need to do that as soon as possible."