OK Huddersfield's goals.
Goal 1.
When the attacker is turning Lindelof inside out Smalling is over by his man as he should be. However once it's clear Lindelof is in trouble and Mooy is bearing down on goal for the pass a top defender would see what's coming and get over to cover it, the pass to his man would be no more 'on' than it already was. Smalling instead stays right by his man and well out of the play.
Goal 2.
Lindelof's mistake entirely but Smalling is jogging nonchalantly far over to the side of them. A top defender anticipates better and makes sure he is closer to the situation and trying to cover Lindelof in case something goes wrong. Again he was well out of the play.
In neither case am I saying Smalling could have prevented the goal but a Rio or a Vidic handles both situations better. Smalling as always was happy to let the game go on around him and catch up to it if he thought he needed to.
Yeah i'm not really sure what he should have done for the first goal? Lindelof is in trouble, but Mata is also over there trying to 'help' Smalling is covering his man the entire time. If he leaves his man open then when the ball comes back out to Mooy, then Mooy can just pass it to his open teammate.
Matic should have done a better job tracking the position of Mooy.
Second goal, it's clear that Lindelof was trying to head the ball to Smalling.
I don't think it's fair to anticipate that your teammate will miss a header, and in doing so get yourself out of position to try and position yourself in the right place if he misses his header.
If Smalling moves out of place in order to try and anticipate Lindelof's header and Lindelof actually connects with the ball, then it becomes a misplaced pass.
If Smalling did what he was supposed to do and stay in his position, then it's not really his fault that Lindelof can't head a simple ball.
Afterwards he makes up a lot of ground to try and recover and narrow the angle between the goal and the goalscorer, including sticking out his leg.
Again i'm not sure what he could have done?
Or what Rio or Smalling would have done better in those positions either?