The likelihood of the rover being responsible is really something only the guys actually controlling it could estimate.
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.
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.