Complex sentence: The 2008-09 season saw a setback when Boenisch suffered an injury ahead of a new season, he became a regular in the first team and spent the most of the season in the left-back position, competing the position with Petri Pasanen.
Split into simpler sentences: The 2008--09 season saw a setback when Boenisch suffered an injury ahead of a new season. He became a regular in the first team and spent the most of the season in the left-back position, competing the position with Petri Pasanen.