That could very well be a possibility.Or, another possibility - and this is a wild brainlapse originated from sleep deprivation - Nick did something bad. Not necessarily "remove from the sport" level bad like sexual harrasment, but something that didn't upset someone important in the team. Banged the boss' daughter, maybe? Or maybe the son?
Maybe they're not bringing Ricciardo in - they're kicking Nick out.
That could very well be a possibility.
I've also read that the decision was not based on race performance, but rather on sim performance. Nyck wasn't getting close to Yuki's laptimes, meanwhile Danny even beat Yuki, instantly.
"chikushō! I of forgot-u to put simulator-chan to the kilometer! Nyck-chan's metrics will of be all wrong! Ah, I of think it won't be biggu problem-u..."