MESSENGER studies of Mercury - Non-relativistic explanation for precession?

My first thoughts on reading this article:

http://www.tgdaily.com/space-features/62234-the-mystery-of-mercury-s-core

"Indeed, scientists have discovered that Mercury's core - already suspected of occupying a greater fraction of the planet's interior than Earth, Venus, or Mars - is even larger than anticipated."

"Essentially, Mercury's core is different from any other planetary core in the Solar System. For example, Earth has a metallic, liquid outer core sitting above a solid inner core - while Mercury appears to boast a solid silicate crust and mantle overlying a solid, iron sulfide outer core layer, a deeper liquid core layer, and possibly a solid inner core."

Funny how the precession of Mercury is also one of the most-touted proofs of relativity.

But given the above article, could it be that these previously unexpected aspects of Mercury could actually be the cause of the precession, rather than general relativity? Earthquakes can change the spin of planets and effect their orbits. Could it be that something about Mercury, which apparently has a core unlike any other in the solar system, is effecting its orbit?

Could it just be possible that maybe general relativity has absolutely nothing to do with Mercury's precession, and that some other effect is at work, and that this much-touted test of general relativity is really no test at all?

Anyway. What are the implications, if any, for relativity? That is my initial thought upon reading the above news article.