Real Madrid midfielder Isco will threaten to join Barcelona on a free transfer if Los Blancos sign Chelsea forward Eden Hazard.
The Spain international was highly instrumental in Real Madrid's triumphs in both La Liga and the Champions League last season, with his great form resulting in him starting the final of Europe's elite competition ahead of Gareth Bale.
He ended the season with 11 goals in 42 appearances, but Spanish publication Diario Gol believe he will offer Madrid an ultimatum should they continue pursuing Chelsea star Eden Hazard.
The Belgian has been linked with a move to the Bernabeu after helping the Blues to the Premier League title last year, scoring 16 goals and contributing five assists in England's top division.
Isco is entering the final 12 months of his contract with Madrid and is willing to risk the wrath of fans by threatening a move to Barcelona, the long time rivals of Los Blancos who recently appointed Ernesto Valverde as their new manager.
Exciting prospect Marco Asensio is also willing to threaten an exit if Hazard is signed, having benefitted from a promotion to the first-team by manager Zinedine Zidane.
However, his game time at the Bernabeu could be reduced if Hazard switches the Premier League for La Liga, having previously plied his trade for Lille in Ligue 1.
Monaco youngster Kylian Mbappe is also said to be interesting Madrid, who recently sent attacking midfielder James Rodriguez to Bayern Munich on a two-year loan deal.