At this stage of his career, the style and formation of Chelsea is perfect for him (at least it was this season). In a back 5 with Rudiger one side and Azpilicueta or James on the other, he doesn't need to sprint around like a maniac and can concentrate on being in the right place and distributing the ball. With Rudiger gone though, things will become more difficult - I'm expecting Christensen to slot in for Rudiger who isn't as reliable and the consequence might be that Silva is forced to do more of what he shouldn't be doing any more - running. We'll see though. Silva could make Christensen a better player.