How do substitutions work in soccer?

Once a player comes off, that's it. They're done. No going back on later, no rotating them in and out, no takesies-backsies.

That's the biggest difference from most other team sports, where players cycle on and off all game. In soccer a substitution is permanent, which is why managers agonize over them and why you'll see a coach standing with a hand on a player's shoulder for two minutes before finally sending them on.

Five substitutions per match, chosen from a bench of nine.

There's a catch that trips up new viewers. Those five subs have to be made across three separate stoppages, plus half time. So a manager who uses one sub at a time will run out of opportunities before they run out of players. It's why you often see two or three players go on together.

For most of soccer's existence there were no substitutes at all. Get injured and you either limped on or your team played a man short for the rest of the game.

Injury replacements were finally allowed in 1958. England adopted the rule in 1965, and managers immediately started gaming it, instructing perfectly healthy players to go down holding a hamstring whenever they fancied a change.

Two years later the authorities gave up trying to police it and just allowed tactical substitutions. Sometimes the cheats win.

Fresh legs. A winger brought on with twenty minutes left is running at defenders who have already covered seven miles. That's not a fair fight, and it isn't meant to be.

Tactics. Swapping a midfielder for a striker to chase a goal, or the reverse to protect a lead. The change is the shape, not the individual.

Game management. A substitution stops the clock in spirit but not in fact, and a player who takes his time walking off is doing his job. Nothing runs down a game quite like a leisurely stroll to the touchline.

Protecting someone. A player on a yellow card who's one bad tackle from a red will often be taken off before he can be sent off.