Celtic great John Hartson has told Leicester City they must be prepared to pay big money if they want to prise Matt O'Riley from Parkhead.

The English Premier League side are reportedly monitoring the O'Riley but their financial situation is such that sales are required before any incomings.

While midfielders Youri Tielemans, Hamza Choudhury and Dennis Praet have all been the subject of transfer talk this summer, it is James Maddison's purported move to Newcastle United that got Hartson talking on the subject of O'Riley's worth.

“O’Riley is massive to Ange Postecoglou in the new season as they try to compete for four trophies," Hartson told Go Radio. "We’ve seen what he has done for Celtic already.

"He’s different class now and only going to get better. He looks very happy, enjoying his football and he’s got Champions League [football].

“I would be very disappointed to see him go after such a short time at Celtic but if the club feels he has to go I would hope they ask for top dollar.

"I see Maddison being quoted at £50million, but that does that make Maddison 10 times more expensive than a player playing in the SPFL. I’m not saying O'Riley is £50m but you would hope for £18m.

“We had the conversation a few years ago when we thought Brendan Rodgers would come in for Callum McGregor but since then he has become captain and led them to more success."