exchange Uchida with Höwedes and you're good to go
Metzelder didn't play solid since him coming back to Germany last season so he understandably warms the bench for promising defenders Matip and Papadopoulos, under Magath and Rangnick the Greek played as DM because both coaches disliked J. Jones and Kluge couldn't fulfill their expectations. Stevens likes Jones because he is a sometimes dirty but hardworking player with great quality that knows how to defend AND how to do some decent build-up play by assisting Holtby. Papadopoulos played a decent DM but his passing skills and insight aren't as developed as Jones'. Nevertheless he and Matip are outstanding defenders and they shows that on a regular national as well as international level.
The main reason for the both of them to play as CBs ahead of Höwedes is the vacancy of the RB position. Hoogland is constantly injured. Uchida was never without controversy, the Japanese lacks the quality in the offense as well as the defense to be an indispensable starter like, for example, Christian Fuchs is as LB, often he makes horrible mistakes and by times seems very careless about his surroundings. Marco Höger is a promising young technical player but more a CM than an RB and surely not the longtime remedy for Schalke's RB problem.
Let's have a look now: Metzelder sucks, Hoogland is nonexistent, Uchida flawed, Höger inexperienced and defensively not that good, Matip and Papadopoulos cannot play RB but are decent CB's, Höwedes plays great as CB but is able to be a RB. And he's getting better and better each week.