Sorloth is on-loan at La Real from RB Leipzig with a €16m option to make the deal permanent.
However, l Diario Vasco reports La Real will pass up the chance to trigger the clause. It's claimed the option expired a fortnight ago.
La Real could yet to buy Sorloth in the summer - at a lower fee.
The Norway international has scored six goals in 39 games so far this season.