From the Laws of the Game, on the FA’s own website

It is an offence if a player: 

  1. deliberately touches the ball with their hand/arm, for example moving the hand/arm towards the ball

  2. touches the ball with their hand/arm when it has made their body unnaturally bigger. A player is considered to have made their body unnaturally bigger when the position of their hand/arm is not a consequence of, or justifiable by, the player’s body movement for that specific situation. By having their hand/arm in such a position, the player takes a risk of their hand/arm being hit by the ball and being penalised

So let’s go through bit by bit. Clearly, the applicable portion of the rule is the second point. There is no argument to be made that Saliba has touched the ball on purpose, it has been redirected into his arm at close range while he had his head down. So then, we are left to decide whether the second point applies to this situation.

A player commits a handball offence when a player touches a ball with the hand/ arm (he did) when it has made his body unnaturally bigger. Did he make his body unnaturally bigger? This seems to be where some people get mixed up, because he certainly has made his body bigger. The rule defines what it means to make the body “unnaturally” bigger however, and it clearly makes an allowance for the position of the hand/arm to be making the body bigger if that movement is a consequence of the current movement for that specific situation.

In this specific situation, Saliba is jumping to head the ball and his arm/hand is in a completely natural position for that motion. Every single player that has given an opinion about this has said that this is completely natural for the motion of lunging to head the ball. This is quite clear. If he was not lunging to head the ball, but standing still as a statue with his hands out? Unnatural position, stonewall penalty, and as the rule states, “he’s taking the risk of his hand/arm being hit by the ball and being penalised”.

However, since he is making a specific movement and that specific movement requires this arm position, he is not in an unnatural position. The rules are clear and feeling does not come into this. I think we all understand how it feels like his arm was far out and its a pen, but the rules are the rules. The ref fucked this up.