Either way we're left with a hole in the midfield because of that, not to mention we have a bigger one on the other side, because Pjanic is not Pogba's direct replacement. Neither is Sturaro.
For me the only untouchables in the midfield are Marchisio and Pjanic. Rincon as backup will do, he's very solid indeed (nothing extraordinary but we need those grinta players and he's decent on the ball). Lemina would be in the mix too but there's something we don't know about him. Otherwise he would have benched Sturaro/Khedira by now.
The rest are more or less disposable to me, because we have too many back ups and not enough real starter quality players. If Khedira continues to play like this, you won't be able to justify his place and salary in the team. Hernanes is second one here I guess, pretty big salary for the impact he has.