Complex sentence: He was forced to retire from football at the end of the 1998/99 season as a result of a serious back injury.Carter made 149 appearances for Millwall, scoring 13 goals in all for the Lions.
Split into simpler sentences: He was forced to retire from football at the end of the 1998/99 season as a result of a serious back injury. Carter, as so, made 149 appearances for Millwall, scoring 13 goals in all for the Lions.