The Northern Ireland international was signed on a season long loan deal from the West London side at the start of the season and part of the deal was that should Blues remain in the Premiership the move would be made permanent.
Six points from their last two games as seen Blues move on to 42 points for the season so far and so Premiership safety looks assured.
"He's a tremendous goalkeeper and we have been delighted with his efforts over the last few months," said Blues boss Steve Bruce.
"I am led to believe that we are very close to completing a deal for him and it is just a case of dotting the i's and crossing the t's."
"There is a fee of £1.4m and the length of the deal is four years. He is 32 but I have no qualms about paying that amount out because he is fit and looks after himself.
"We are delighted to have him on board because he has been terrific all season. To be fair to Fulham, they have got two outstanding goalkeepers and the one thing everybody wants to do is play on a Saturday.
"Maik is too good a keeper to be a number two. I wouldn't swap him for anyone. Everything about him, the way he looks after himself, his professionalism, the way he is as a lad makes him the perfect pro."
