PSR-2, while dictating style for the sake of readability, doesn't really dictate whether or not what you're asking is acceptable, at least according to my understanding of it.
What I would say, though, is that if you're planning to invoke a method from someClass, what I would consider far more readable would be using the scope resolution operator, like so, which removes the requirement of instantiating the object using the 'new' keyword:
$data = someClass::getSomething($x);
This is functionally equivalent to your syntax, but more readable.