The Bluebirds have released five out-of-contract players since the end of last season.
"It's okay to say you want to move, but people have got to want you," Mackay told Wales Online. "We will take a look at the outs as and when they come in.
"Beyond September 2 we can always loan. Right now, we are not actively out there selling players."
Cardiff are back in action tonight when they travel to Accrington Stanley in round two of the Capital One Cup.