Complex sentence: In 2008 his contract expired, and RCD Espanyol signed him; he made his senior debuts in the 2009--10 season, playing four games with the B side, with the club being relegated from the third division.
Split into simpler sentences: In 2008 his contract expired, and RCD Espanyol signed him. He made his senior debuts in the 2009--10 season, playing four games with the B-side with the club being relegated from the third division.