The 19-year-old is widely regarded as one of the best young centre-backs in European football, with his performances over the last 12 months drawing a host of outside interest.
Barcelona and Bayern have both been strongly linked with the Frenchman, but the player has hinted that his long-term future is with Bilbao.
"I want to focus on playing in the Champions League with Athletic. I won't talk about anything else," he told reporters.
"I'm not focused on rumours."