..and would also leave Santon open to getting ripped apart every game. Jonas goes then fine, but then we need an experienced proper left back.
Santon can learn how to defend. Or be dropped for Haidara/Mbiwa
Haidara makes Santon look like a great defender.
Anyway, a creative, fast forward in Jonas' place would offer far more protection than Jonas who gives the ball away constantly and offers no attacking threat to pin a side back on the left.