When we play a back four, the DM is a pseudo-CB as the FBs go flying. Want Yaya in our back line on the break against their forward line? Good luck, mate!
Late in games, KDB has dropped back only because of attacking subs that leave us light at the back or in the middle, and because he can go both ways....it has nothing to do with zfernandinho not being able to do the job. In fac,t last time it happened was because Ferna went to FB!
Playing Yaya or Gundogan in the middle of a 4-3-3 against Liverpool is suicide.
I don't think the Yaya v Fernandhino issue is quite so clear cut. Fernandhino undoubtedly is more mobile and defensively will be more effective against their forwards. But Yaya would give us more control and would better stretch the play forcing them back, Fernandhino is more likely to give the ball away in our half. I think its 50:50 as to which player would be the most effective against Liverpool. And I don't expect Pep will play both of them.
I would be very surprised if Gundogan is fit enough to start, expect to see his first start at WBA.