Following Nouha Dicko's departure for Wolves on Monday and with Grant Holt on the verge of joining Aston Villa after undergoing a medical on Tuesday morning, Rosler is in need of more attacking options.
Maynard has been linked with Latics after featuring in just 10 Cardiff games this year and watched Saturday's 3-0 win over Bournemouth from the stands.
Rosler did not confirm whether Maynard's move would be a permanent deal or a loan deal, although he has recently stated he would prefer the latter in the current window.
"We are planning a medical on him," Rosler told Sky Sports News Radio. "We worked hard on this one but it's not over the line."
The 27-year-old striker has been a prolific scorer in the second tier having had spells at West Ham and Bristol City as well and Rosler is hopeful that, following a serious knee injury last season, Maynard is ready to spearhead their promotion bid.
The German added: "He's at the stage of his career where he wants to play regular football again after his injury. He wants to prove a point to himself and also to the people.
"That's a perfect scenario for us; it matches our ambitions. We want to prove a point, we want to go up we want to go into the play-offs and I think we can give him the platform to perform again.
"I will be patient with him because he has not played in a while. But, he's fit, he's ready to go."