If you want to keep him and he wants to stay, and you can cough up 15-20m € in summer, he won't be heading back.
Maybe. There's too many variables, too early to predict anything.
The club is up for sale. It might be sold and money might not be an issue for next ownership, and we might go for the best CM on the market regardless of valuation. Like spunk 100m on Frankie De Jong or something.
Or it could still be up for sale with no money available for transfers.
Also last year's target, Rabiot, will be free. He might still be ETH's preference, instead of paying 20m for Sabitzer. Who knows.
Like I said, too many unknowns. Sabitzer's performances included.