This new rule regarding substitutes could have a significant effect on football

A good idea?

A fourth substitute will be allowed in extra-time during Fifa football tournament's in 2016, including the football at this summer's Rio Olympics, and the Club World Cup later this year. The International Football Association Board, who set football's rules, changed the rule either this month and its trial which was approved by Fifa on Friday afternoon. https://twitter.com/richard_conway/status/710793066349785088 According to a Fifa statement: "Following the recent decision by the IFAB to allow experimentation with a fourth substitution in extra-time, the Fifa executive committee agreed for such experiments to be conducted this year at the Olympic football tournaments, the Fifa Under-20 Women's World Cup in Papua New Guinea and the Fifa Club World Cup in Japan." The extra substitution in extra-time could have a significant effect on a manager's tactics, or could be used to aid an injured player, during knock-out ties, and will come into effect from June 1. If the the trial is deemed successful during the tournaments, it could become a permanent fixture in future Fifa tournaments.