The blues number two just failed a fitness test to be in contention for a place against George Burley's side after picking up a hamstring injury in the closing minutes of last Wednesday's draw against Nottingham Forest.
However Wilnis is said to be making good progress, and according to Joe Royle, will return to training on Thursday: "Fabian Wilnis is expected to return to training on Thursday. He didn't play against Derby, but he was close." explained the blues boss.