Mackay is understood to have earned a £1 million bonus after guiding the Bluebirds to Premier League promotion.
But it appears there are no plans to extend his stay beyond his three-year deal.
Borley told the Telegraph: "I'm sure that will come around at the appropriate time. Malky's not one to move around, to be fair. There's a great loyalty with him.
"When we took him from Watford, it was all done the right way and he insisted on it being done the right way. I believe he's got a very healthy contract anyway."