Complex sentence: He came up through the ranks of Athletic Bilbao where his older brother Aitor was a player at the time, and first appeared with the main squad on 14 May 2000, playing 15 minutes in a 0--0 La Liga away draw against RCD Espanyol.
Split into simpler sentences: He came up through the ranks of Athletic Bilbao where his older brother Aitor was a player at the time. He first appeared officially with the main squad on 14 May 2000, playing 15 minutes in a 0--0 La Liga away draw against RCD Espanyol.