What makes the casting call a bit suspect is this: The film originally started its production in Budapest last month, but has shifted to the United States to film the majority of the movie.
They 1. Make it seem like they're already filming the US, which obviously isn't true. And 2. They're not gonna film the majority of Red Sparrow in the US. It's just not possible. A few scenes perhaps, but not more than that. Especially not in Texas. We know they're wrapping up in London according to Jennifer's makeup artist. And it's also been mentioned that they're gonna be in Budapest until April. And I don't see that having changed all of a sudden.
So I'm not totally sure I buy that the casting call is all that reliable. Not the full content of it at least, because there is no way that they're gonna switch over to film the rest in Texas and the US in general. In the book, there are US scenes set in Washington, New York, Los Angeles and New London, Connecticut. And perhaps some other location that I've forgotten. They might have added some scenes and changed it up a bit and will show Nate's background a bit, but filming the majority of the movie in the US? I just don't see it.