The problem in this case isn't just VaR but the wording of the Law. Kicking a player is only a foul if done 'in a manner considered by the referee to be careless, reckless or using excessive force'. 'Careless is when a player shows a lack of attention or consideration when making a challenge or acts without precaution'. That wording is absurd and unclear but makes the judgement of the referee crucial. If Atkinson didn't see the kick then he made a clear error and it should have been overturned by VaR or at least referred back to him to see if he thought it was careless. If he saw it but judged it not to be careless then there is no case for VaR to overturn it.Probably should have done. It was a foul even though it was only a slight touch on him. It was also a long way back at the start of the move.
It seems as though they are intent on not wholly undermining refs through VAR.
Of course what the Laws ought to allow for is that football is a contact sport and there will inevitably be minor kicks and other impacts that should not be penalised at all.
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