The 21-year-old Scotland international, who scored 18 goals last season and spent a month on loan at Sheffield United, has reportedly attracted interest from Premier League sides Southampton, Everton, Wigan and Swansea.
Blackpool say they are yet to recieve a formal offer for their player but Holloway insists one club has made an illegal approach for the midfielder.
He told the club's official website: "Somebody has made an illegal approach and we can prove that.
"I'm not very happy about that and the Football League and the Premier League will be informed about that.
"The boy is a fantastic young man - we've had a good chat about it, me and him - and he's as committed as ever to playing for Blackpool."Meanwhile, Holloway also revealed the club are no closer to agreeing terms with QPR striker DJ Campbell in a deal to bring him back to Bloomfield Road.
He told The Daily Mail: "We are as close to re-signing DJ Campbell as me wearing high heels and calling myself Sheila."