Celtic chief Peter Lawwell has urged Virgil van Dijk to give them one more year.
The Dutch defender has been linked with Everton, Southampton and Newcastle United in the Premier League.
"My view is that one year is far too early for him," said Lawwell. "He needs another year in the Champions League.
"I've spoken to Virgil's agent. We don't want to sell him. We have a manager who I think will make him - and all our players - better.
"If I was his advisor, I would be saying: 'Forget this year, let's stay and develop'."
