We are speaking of Pogba alternatives, so whoever comes in would be the long term heir to yaya's position. Even if we got Pogba it's difficult for me to see who he would replace in the team that fronted up against Chelsea in the short term. Fielding a team with yaya and pogba together in a midfield of 2 would be suicidal so the only 2 options would be to to replace yaya with pogba, but IMO yaya is currently the better player, or to push Yaya forward and Silva out wide and sacrifice navas, which is not ideal as Silva plays his best football behind the striker.