The departure last month of Toby Agdestein has left McKay as the only recognised striker in the squad.
That is not a major concern for Hughes, though, after watching midfielders Nick Ross and Marley Watkins excel in an advanced position during a training match.
"It would obviously be a blow to lose Billy to injury but we can shuffle the pack a little bit," said Hughes. "Before the [Scottish League Cup] semi-final we picked the starting line-up in training, playing another team from our squad against them. Nick Ross was causing all kinds of problems in a different position and Marley Watkins was outstanding."