What are the positions in rugby union, and when can a player be replaced?
I · Intermediate · The fifteens game · 1 of 6A team has eight forwards and seven backs. The forwards form the scrum, and the laws name only its places: two props and a hooker in the front row, two locks behind them and three back-row players. Up to eight replacements may be named. Replacements come on only when the ball is dead and the referee agrees, and a player replaced for injury may not return.
How it works
- The scrum places: "two props and one hooker in the front row and two locks in the second row. Three back-row players from each team complete the scrum."
- The backs: the other seven. Their names (scrum-half, fly-half, centres, wings, fullback) are common usage, not law.
- When: "Replacements are made only when the ball is dead and only with the permission of the referee."
- Front-row cover: a squad of 23 must include six front-row players. Smaller squads need fewer.
- Named in advance: only the front-row players a team names before the match may play in the front row at a contested scrum.
- Uncontested scrums: if a team cannot field a trained front row, scrums become uncontested, still with eight players a side.
- Injury: "An injured player may not return once replaced."
- Concussion: a player with concussion or suspected concussion "must be immediately and permanently removed". This is "Recognise and Remove".
- Blood injury: a temporary replacement for up to 15 minutes of actual time.
- Head injury assessment: at approved matches, a temporary replacement for up to 12 minutes, even if all the replacements have been used.
- Coming back on: a player replaced for tactics may return only in listed cases, such as replacing an injured front-row player or a player with a blood injury.
- Rolling replacements: a match organiser may allow them at defined levels, with no more than 12 interchanges.
The glossary has the forwards, the backs, the replacement, the front row replacement rules entry, the blood injury and the head injury assessment.
Tricky cases
A prop is shown a yellow card and the team has no other prop on the field. What happens?
The team nominates another player to leave the field so that a replacement front-row player can come on. The nominated player may not return until the ten minutes are over.
A team's last front-row replacement is injured. Must it play on with a back in the front row?
No. The referee orders uncontested scrums, still with eight players a side. In elite rugby, a player whose departure caused this cannot be replaced.
A player comes back on after a blood injury. Does that use up a replacement?
No. A blood replacement is temporary. If the injured player is not back within 15 minutes of actual time, the replacement becomes permanent.
Is a number 8 the same as a back-row player?
Yes. The number 8 is one of the three back-row players and binds at the back of the scrum. The number is common usage. The laws mention the number eight only once, on when a scrum ends.
Why the rule exists
The front row takes the force of the scrum, and an untrained player there can be badly hurt. That is why the laws are so detailed about front-row cover and why scrums go uncontested when a team runs out of front-row players. The injury rules put player welfare ahead of tactics: a concussed player is off for good.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Scrum places | Two props, a hooker, two locks, three back row | WR Law 19.5 |
| Front-row cover | Six in a squad of 23, fewer in smaller squads | WR Law 3.8 |
| Uncontested scrums | Still eight a side | WR Law 3.15 |
| Sevens | Up to five replacements, three in a scrum | WR Sevens Law 3.4; 19.5 |
From the rule book
World Rugby, Laws of the Game: Rugby Union 2026, Laws 3 and 19. Checked 21 October 2026. Official document: Laws of the Game, Rugby Union 2026 (PDF).