Groningen director Hans Nijland has confirmed that the club have received an offer for highly-rated youngster Virgil van Dijk.
The defender, who has been widely linked with a move to Celtic, was part of the Netherlands Under-21 side that reached the semi-finals of the European Championships in Israel this summer.
"There is a bid from a foreign side," Nijland told Voetbal International.
"The offer and our valuation are not on the same line at the moment. We want to keep Virgil but we understand his ambitions. It's an exciting period."
Van Dijk played every league game for the Dutch club last season.
