The Knight in the Area (2012)

Kakeru Aizawa is the younger brother to Suguru Aizawa, a soccer prodigy belonging to Japan's under-15 national team. Prior to the series, Kakeru quits his position as a forward after a traumatic experience prevented him from playing with his left leg and settles for a managerial position. After the two are hit by a truck, Suguru dies and has his heart transplanted into Kakeru. With it, Kakeru returns to soccer to achieve his brother's dream of winning the World Cup.