Complex sentence: He made his professional debut on 22 December 2007 as an added-time substitute in a 3--0 Scottish Premier League victory at Motherwell, and finished his first season with five appearances, the last three of which were starts.
Split into simpler sentences: He made his competitive debut on 22 December 2007 as an added-time substitute in a 3--0 Scottish Premier League victory at Motherwell. He finished his first season with five appearances the last three of which were starts.