Zigic, who played for Serbia at the World Cup finals, has found it difficult to adjust to life in the Premier League since arriving from Valencia in the summer, starting just one match and failing to get on the scoresheet. His only goal so far came in the Carling Cup success over League One side Milton Keynes Dons.
McLeish has faith in Zigic to eventually show his true worth. He said: "Nikola is still adjusting to the English game. It is hurly burly, 100 miles an hour. On the continent he is used to balls being laid up to him and cushioning it and laying it off and keeping the play moving.
"It is a totally different game to the Spanish system and also the Serbian system as well. The players tend to get lazy as well when there is a big guy in the team because they just launch it forward. But we've got to try to get into the right positions to give him the right service.
"Nikola has still got to find some sharpness in his touch and things like that. But I am sure he will make a contribution.''