Junior Firpo injury: When could the Leeds United defender return? Concussion guidance for Premier League players explained

The defender collided with Whites 'keeper Illan Meslier in the first-half and, though initially fine to carry on, later left the field of play.

Firpo made way for 20-year-old Cody Drameh in the 69th minute as the Whites were chasing the tie, with West Ham leading 1-0.

After the conclusion of the game, which sealed the Hammers' passage to the fourth round with a 2-0 victory, Firpo took to social media to confirm that he was feeling well.Last season, following guidance from medical experts, the Premier League tightened up regulations regarding concussions, including the introduction of concussion substitutes, which allow teams to make up to two additional changes if players are suspected to be suffering from concussion.

This did not apply during the Whites' London Stadium visit on Sunday, as the change of personnel in defence did not exceed the limit of five substitutes allocated for FA Cup ties.

But what does the FA's guidance on returning to play from concussion mean for Firpo and his participation in upcoming fixtures?

Here's what you need to know:

What is a concussion?

A concussion is an injury to the brain.

In more than 90% of cases, concussions do not lead to a loss of consciousness, or passing out.

All concussions should be regarded as potentially serious, and should therefore be carefully managed.

If concussion is managed incorrectly, further injury could occur.

Concussions can be caused by a direct blow to the head, but may occur when another part of the body is disturbed, causing rapid movement of the head (eg. whiplash).

What are the symptoms of concussion?

Common symptoms of concussion include headaches, dizziness, memory disturbance or balance problems.

Other signs to look out for include confusion, irritability, fatigue, visual disturbance, light and noise sensitivity, seizures.

Players suffering concussion may have a vacant look and be slow to get up from the ground.

Video footage, if available, will also help to identify the severity of a concussion.

Usually symptoms begin immediately after an incident, but there can be a delay.

What happens if a player suffers a suspected concussion?

Players must be removed from training or substituted off the pitch as soon as symptoms of concussion emerge.

If no symptoms are evident after a knock, the player may continue, and a clinical assessment will be made at half-time and full-time and the club will deliver a report at the end of the game.

If symptoms emerge after the incident, as was the case for Firpo, the player will be removed from play.

How many concussion substitutions can Premier League teams make?

Each team can make two concussion substitutions per Premier League game.

If two have been used and a third concussion is suspected, the team must use one of their three standard substitutions or, if none remain, withdraw the player and compete with ten men.

Do concussion substitutes give an unfair advantage?

When someone with suspected concussion is replaced, the player coming on will be more fresh than the player departing.

In recognition of this, the opposing team will be given an additional substitution to level the playing field.

What happens after a concussed player is replaced?

Players must not return to play on the day of a concussion.

After the game, the player will undergo a medical assessment. If no concussion is found, the player will be cleared to return to training.

If the player is concussed, medical staff will follow the FA concussion guidelines when assisting the player’s return to action.

All clubs who have used a concussion substitute will be required to submit a report, including details of procedure and the player’s medical information, within seven days of the player’s return to training.

In the first 24 hours after suffering a concussion, players should not be left alone or consume alcohol.

What are the FA concussion guidelines?

Firpo’s return to play will depend on the outcome of medical assessments.

The FA recommends a progressive return, bringing players back into action with a six-step process.

Rest, both physical and cognitive, is central to treatment and forms the first step. This recovery period lasts a fortnight, but is reduced in enhanced settings, including professional clubs.

Steps two to five, which will take 24 hours each, involve a staged return to action, moving from light exercise, to football-specific exercise, then non-contact and contact training.

Step six is return to play which, in enhanced settings such as Leeds United, can happen on day six after the incident at the earliest.

This means that, if Firpo was found to have suffered a concussion, he could be eligible to feature in the Whites’ Premier League clash against West Ham, provided he satisfies the club medical staff at each stage of the recovery process.

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