Athletic Bilbao president Jose Urrutia has told a press conference the club could take action against Bayern Munich over the Javi Martinez deal.
• Martinez arrival boosts Bayern
Bayern finally concluded their long pursuit of Martinez last week when they paid his €40 million release clause, but he had earlier undertaken a medical without his club's permission.
Urrutia said: "Athletic are assessing whether they will take action against Bayern. The player was under contract, during the protection period established by FIFA. The player underwent a medical with the German club without Athletic's permission. Whether we can or should denounce Bayern is being considered."
Urrutia also revealed that Martinez' agent had told him before Euro 2012 that the Spain international wanted to leave Athletic. After that, Martinez "told me on the phone what I did not want to hear", the president said.
The negotiations for Martinez had dragged on for several weeks over the summer, and Bayern coach Jupp Heynckes had said during the player's official presentation on Thursday: "When you understand the Basque soul, you know why it has taken so long." It appears the saga could yet linger on.