He told the Wigan Evening Post: "Frank will still play a vital part here, you can't have enough people like him.
"He's been in the game for years, has a knowledge as good as anyone's, and is extremely good at his job. When I came to Wigan, it was always my intention to keep him - and Frank has done a little bit of everything.
"For example, last week he took one of the coaching sessions. Then on Saturday, he was at Hampden watching Scotland. He's a valuable member of my team, a proper football fella and I like him a lot.
"It's no secret I wanted him as my assistant manager when I first took over at Birmingham.
"That speaks volumes about his loyalty."