Playing at the back is the easiest position in football, You have the whole game in front of you and any decent defender should be able to play anywhere across the back four if needed. It is all about getting your positioning right and your awareness of where your team mates are as well as the players you are defending against. This is what lets Yoshida down. He gets away with it more when he plays at CH because he has players either side of him but he still manages to get himself in the wrong place at the wrong time. As for dithering on the ball the other day, again, his brain doesn't seem to engage quickly enough at times. As Whitey said, you rarely if ever see a Premiership footballer lose the ball like that. It was a schoolboy error.