Complex sentence: He made his debut in the Norwegian Premier League in Lillestrøm's season opener away against Stabæk as a right fullback, a role which he retained for the remainder of his time with the Norwegian side.
Split into simpler sentences: He made his debut in the Norwegian Premier League in Lillestrøm's season opener away against Stabæk as a right fullback. This was a role which he retained during his time with the Norwegian side.