Clarence Harding, 26, was rushed to hospital during a cup match between his team, Gravesend Rugby Club, and Maidstone RFC on Saturday. Gravesend have demanded an investigation after surgeons said Mr Harding is unlikely to regain the sight in his right eye.
Mr Harding, who was playing number eight, said:
"It was over in an instant but it dawned on me that something pretty serious had happened. The ball was nowhere near my head at the time."