Cohen will be sidelined for nine months following the injury he picked up during Forest's 1-1 draw with Derby.
Wigley told reporters: "It's a huge blow for Chris and the club. He is a very good player and a fantastic person. We will miss him him on the pitch and off it.
"But I have no doubts he'll come back. He knows what he has to come through."
The 27-year-old has scored 12 goals in 232 appearances for the club that he signed for in 2007.