I believe his presence in Chelsea squad will boost their weak defence and with age on his side and a long term contract agreement, I believe Tuchel will norture and mould this guy to a world class defender he is very young with a bright future personally I think his sign-on looks too expensive to me,
Already, Wesley Fofana is a very good talented defender and no need of moulding or remoulding the young player, The only Job left for Thomas Tuchel to do is using him well in the right place/position suited for him and that's all, Fofana I know will prove his world class.
And as of the signing fee, Not too expensive in my opinion, looking at his age and what he got to offer in Chelsea and if we have him living up to expectation.