The concussion guidelines that could mean a Sunderland defensive reshuffle explained

Cirkin had excelled against Bolton Wanderers, registering his first assist for the club with a cross for Carl Winchester's early and ultimately winning goal.

But his afternoon came to an early end after an aerial challenge with Lloyd Isgrove led to both players being substituted.

Cirkin was initially ruled able to play on, but was replaced shortly afterwards.

Crucially it was ruled to be a concussion substitute, which under new rules allows clubs to make one further change.

That allowed Lee Johnson to replace Callum Doyle with Bailey Wright when the former began to suffer with a minor back problem.

Cirkin has been monitored by the Sunderland medical staff and if confirmed that he did suffer a concussion, he will then follow the FA's 'Return to Play' guidelines.

In a professional environment, that requires a 24-hour period of rest. If the player is then symptom free, they are allowed to begin a phased return to training.

That included a gradual increase in workload over a three-day period, before a doctor then makes a decision as to whether the player can return to full contact training.

Providing the player remains symptom free it is a six-day programme.

However, in the case of 17-19 year-old players the initial period of rest rises to seven days.

If Cirkin has suffered a concussion, Niall Huggins is his likely replacement to face Cheltenham.

19-year-old Cirkin would also be a doubt for this weekend’s trip to Portsmouth in what would be a significant blow for Johnson.

Denver Hume is set to make his senior return in the Papa John’s Trophy next Tuesday.

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