The reigning Formula Renault 3.5 champion joined Hilmer from the second round of the series in Bahrain and has competed in five rounds for the German squad.
Frijns won in his third GP2 outing in Spain and has scored 45 points in total.
The Dutchman said on Wednesday however that he has run out of budget to race in GP2.
"So that was it then. No money no drive," Frijns wrote on Twitter.
"Winning championship [sic] is not enough these days! Good luck for all the GP2 boys!"
Quaife-Hobbs, the reigning AutoGP champion, has raced in GP2 with MP Motorsport this season and is currently in 16th place with 23 points.
GP2 organisers said Quaife-Hobbs's replacement at MP would be announced tomorrow morning.