Complex sentence: In the 2013 summer, Sola joined Athletic Bilbao on a five-year contract with a €30 million buyout clause--he had already played youth football with the club, from ages 12--17.
Split into simpler sentences: In the 2013 summer, Sola joined Athletic Bilbao on a five-year contract with a €30 million buyout clause. He had already played youth football with the club, from ages 12--17.