Hull City chairman Adam Pearson has already been alerted to the news and says the club will now be persuing their interest in the 30-year-old.
He said: "We understand Nicky is interested in coming to play for Hull City and he is certainly a player who, if he is available, then we will have a look at to see if he fits in with our current structure.
"We are not prepared, however, to break the current level of pay. We are strict on that point so we will need to see what can be done.
"Nicky being handed a free transfer at Leeds is certainly an interesting development and we owe it to ourselves and our supporters to investigate any options open to us. We will be keeping an eye on developments."