You make slight adjustments.
All I'm suggesting is ditching the super-high line we hold, by dropping the defence about ten yards deeper.
That concedes some space to opposition in other areas of the pitch, but it is a slightly less risky option with the players available right now.
while sitting a bit deeper might grant the opposition less space behind the defence to play the ball to, it causes other problems.
a high line does make the space in midfield tight (because the players are closer to each other). if you adjust that, then there is more space for the opponent to run and play to in their own half. this will make it more difficult for our midfield to stay close to the opponent, because they got more space then.
the problem is, there is no easy tactical adjustment that will fix the loss of sissoko.
if there was one, trust me, someone with the experience of ranieri would have used it
simple as that ...