Could be, but for the ones denying we are after Sarri. Look at from this perspective, Chelsea or Sarri has never denied it, neither have Juventus, even if it's often the current club who go out and deny rumours.
Just because it's Sarri (some fans here thinks he is shit) some believe we can close it instantly, it's not that easy, money is involved, Sarri has a contract, Chelsea need a replacement ( could even be so that they are trying to change his mind about leaving) if Chelsea really want Lampard as the rumours say, look at Derby trying everything to keep him. So this could take some time.