The Serbian striker was not included in Lee Clark's squad for their 2-1 Championship win over Bolton on Tuesday night, refuelling rumours that he could be on his way out at St Andrew's.
But McDermott insists that Zigic was not played purely from a tactical viewpoint and is positive he will be staying put in the West Midlands.
"Ziggy just wasn't selected for the game - the manager decided to go with a little bit more pace," said McDermott.
"It was just a tactical thing. He is fit. It was just the manager's choice."