Substitutes have played important roles in the World Cup, and will continue to do so in the next four years.

FIFA committee will advise before the start of the World Cup 2018 that four substitutes will be allowed for extra time in the match.

"I think that's an idea that we will put" to football's rules-making panel, agrees Gerard Houllier, a FIFA committee member, on Wednesday.

Three replacements may be permissible, even if knockout stages exceed the 30 minute allotted time before the end of the game.

According to Houllier these changes will lessen muscles pains and injuries among players.

"It's a good idea. Only in extra time. Maybe if someone is injured, why not?" the former France coach adds.

Substitutes have scored an admirable 29 record-breaking goals, thus far. The last record was 23 at the World Cup in Germany in 2006.

"Substitutes play such an important part because they come with a freshness and attitude," Houllier said, in a press conference. "Nearly a quarter of (all) the goals have been scored in the final 15 minutes of the game."

The goals have usually made a lot of difference in the game, but not necessarily bringing in the winning end.

Klaas-Jan Huntelaar late strike caused Netherlands to lose to Mexico, 1-0, in Sunday's round 16. Huntelaar beat Wesley Sneijders for a penalty shootout.

On Monday, Belgium could not win over challenging United States goalkeeper Tim Howard .This is because substitute Romelu Lukaku went on extra time against Kevin De Bruyne.