Kobayashi was dropped for the Belgian Grand Prix and replaced by three-time Le Mans winner Andre Lotterer. The team are believed to have wanted Roberto Merhi in the car this weekend, but as the Spaniard does not have a superlicence he will only run FP1.
Lotterer was reportedly offered a second race with Caterham, but turned down the chance as he wanted to run every session due to his lack of F1 experience. As such, Kobayashi was drafted back into the lineup.
Speaking to Autosport ahead of this weekend's race, the former Toyota and Sauber driver admitted he is not pleased with the situation.
"I am here for the sport of racing, but looking at the last couple of weeks I think it's more political stuff happening than sport.
"We've had talks with lawyers and this is what we have right now. I have a contract.
"I am a Caterham driver and it's not up to me. If they say simulator I do simulator, if they say stay at home I stay at home, if they say race I race.
"Of course I'm not happy but this [situation] I cannot avoid."
Kobayashi's future beyond this weekend is unclear. Merhi could make his debut in Singapore, but competing on a street circuit at night may be seen as too great a leap for the F1 rookie. As such Kobayashi may remain in place for another race, though he could then be dropped for the following event - his home race in Japan.