Chelsea and Liverpool are still to settle on compensation terms over Dominic Solanke.
Solanke left Chelsea for Liverpool on a free transfer at the end of last season.
Rules regarding home-grown players dictate that Chelsea are still entitled to compensation, even though his contract had expired, because he is under 24.
Chelsea rejected Liverpool's offer of £3m, insisting Solanke is worth £10m.
Chelsea's case had already been strengthened by Solanke's performance at the Under 20s World Cup, with the striker finishing top scorer and named player of the tournament as England won the tournament.
And the London Evening Standard says his call up to Gareth Southgate's senior squad will be used by Chelsea to argue their case when the tribunal sits.