Right now it’s Gyorkeres’ spot to lose. He was the big summer (for a while!) and he’s been up to speed and gelling with those around him. I think Havertz is going to have to impress in whatever spells he gets and hope Gyokeres hits a dry run at some point to have any chance of staking a claim for starter.
It’s by no means guaranteed he gets up to speed, match fitness and form any time soon given his time out and previous attempt to come back.