Complex sentence: In 2005--06 he made his professional debuts, playing in one second division match; his fate did not improve in the following season, as he only appeared in seven games (out of 42) for SD Ponferradina, which eventually got relegated.
Split into simpler sentences: In 2005--06, he made his professional debuts, playing in one "Segunda División" match. His fate did not improve in the following season, as he only appeared in seven contests (out of 42) for SD Ponferradina, which eventually got relegated.