SM001 yeah, if the only way for you to block the ball is to move towards it with your arm, then tough luck you are not in a position to block the ball.
Otherwise you could claim that players should be allowed to win the ball with high studs, if that’s the only way they’re able to reach it. Tough luck, just don’t make the tackle.
(and his arm wasn’t properly at his side until after the ball hit it)