He looks like he's back to the Zouma before the horrific injury a few years ago.
I genuinely thought the injury had knocked a bit out of him, after the excitement of getting him in it looked at times during the winter months like he wasn't full commiting to challenges anymore, not the same aggressive player he was early in his career, perhaps a lingering mental block that was holding him back but the past couple of months as confidence has grown he's back to being the defender that's all over the attacker before he's even had time to take a touch.
Even looks like he's vastly improved on the ball and much more comfortable now playing on the left.
Personally think Chelsea would be silly to let him go but i'd absolutely take him here long term (gives me hope to stick with Mina, let him settle and hopefully get a good run of games without injuries to truly judge his ability)