I reckon the thing about Ledley King is the fact that against the top teams away he just doesnt have it in him to compete for the whole 90 minutes. Unfortunately in the past seasons he hasnt played enough against the top teams away for us to know if this season is a one off, or if his legs look like going.
It's quite possible the plan for this season was King would play along Kaboul/Dawson at home, with Gallas switching in for away games - which would work in principle, if not for the fact Gallas has been crocked more often than not this season.

