"Only two options have so far been identified as the rock’s source: 1) The rover either “flipped” the object as it maneuvered or, 2) it landed there, right in front of the rover, after a nearby meteorite impact event."
So, you know, our leading theories are that either the rover did it somehow, or, approximately 8-10 orders of magnitude less likely, we just witnessed a meteor strike. Really, nothing in between those two?
Well the first thing that came to my mind when reading the title was the phenomena of moving rocks in Nevada [1]. It could be similar but unlike them this doesn't seem to leave any trails.
I wouldn't discard weather as the cause, and I'd consider weather long before meteorites. While the martian atmosphere is very thin, it packs a good punch speed-wise. Maybe in edge cases that could be enough to pick up small rocks and have them rain down somewhere else (similar phenomena exist on Earth).
Another hypothesis would be that the rock was ejected by a gas vent. I have no idea about the temperature conditions at the rover site, but a gaseous plume could carry solid material with it if the release was forceful enough - showering the surrounding area with rocky material.
But all things being equal, I'd bet on the rover.
Honestly its not like we have many real options. The rover flipped it or it fell there sound good too me. The area is pretty open there so it didn't crack off another rock, let alone the shape precludes that.