"We have received a bid," Preston chairman Derek Shaw told the club's official website.
"But we have had a written request from the club asking us not to reveal any details, so I was very surprised to see the information in the press.
"We are led to believe Ricardo and his agent will meet with the club in the next couple of days but are not going to discuss this any further at the moment as if the situation were reversed we would not be happy and we know that the details of the bid were not released by Portsmouth."