Doesn't change the fact if they lose Akanji means they need a left foot centre back more than a right foot.
Hummels is pretty much nailed that central role. Can (Piszczek) Hummels Zagadou (Rojo). Unless you can be so certain that Zagadou is no longer injury prone.
Leaving the right side to a midfielder and a 35 year old fullback, while making sure that on the left side either Zagadou or the new signing will be benched, all but ruling out the possibility to change to a back four?