Complex sentence: In his first season with the team, he scored one goal in 13 league appearances, and at the end of the 1999--00 season, Cagliari were relegated to Serie B, where they would remain until the 2003--04 season.
Split into simpler sentences: In his first season with the team, he scored one goal in 13 appearances. At the end of the 1999--00 season, Cagliari were relegated to Serie B, where they would remain until the 2003--04 season.