Højlund is going to be Napoli's main CF in the absence of Lukaku. His return will probably be no earlier than mid December for now.

The new signing Højlund is on loan there for now of course. There is a buy option of 44 million euros as far as I know. But let's see whether he will perform that good to trigger it by Napoli.
He couldn't prove himself at either Atalanta or Manchester United so far...