If he can stay healthy he can easily play for another 4-5 years together with Martinez, he has the speed, reading the game great, calm, good in the air, strong, leader - still of the best defenders and big reason why we had great defense (probably least concede goal per games in Europe if we did not mess up the 7, 6 and 4 goals against city, liverpool and Brentford). Also a big reason Martinez could get a good start even though the 2 first games when everybody was writing him of claiming he was way to short to make it in the Premie League. Those two will be even better this season with Onana in goal since they both are great ball handlers and can easy pass through pressing without just shooting away the ball. Having Casemiro in front of them helps also.