According to Blick newspaper, Hulkenberg and his manager Werner Heinz are having "sleepless nights".
According Force India's sporting director Otmar Szafnauer, Pirelli's mid-season tyre specification switch badly hurt some teams like Force India.
"The opportunity is there that Giedo could come to us to drive" - Michiel Mol, a key shareholder at Force India.
While it appears Sauber has two young drivers with the cash flow, the Russian may not be ready for Formula One, leaving a spot for Hulkenberg to remain with the team.
Felipe Massa was sixth fastest in the final Formula One qualifying segment but he will now start the Spanish GP from ninth. Esteban Gutierrez lost three positions.