I agree that something is not quite right with Sane at the moment but i'm not sure it's tiredness - at least not physically, as he's been rotated a lot more than most. I think he's just a bit off form and lacking a bit of confidence. It feels to me like it might be more helpful to give him the opportunity to play his way back into form across these next three home games rather than finding himself out of the team but starting Sane and having Diaz play the last 20/30 minutes seems a natural way to show faith in him and ease his workload a bit.