Early migration of Jupiter to within 1.5 AU?

Just read an article from Astrobiology Magazine.  Researchers from Southwest Research Institute have recently released findings from many simulations of solar system formation and orbital dynamics which suggest that Jupiter may have, at one time, migrated to within 1.5 AU of Sol.  This may explain the small size of Mars relative to Earth and Venus, as well as the mixed population of the asteroid belt.  Very interesting.  I'm sure this new model will be tested and re-tested before anyone is certain of its likelihood, but it is still interesting.  If Jupiter could have migrated inward long ago and then later migrated back out to where it is now, that may shed some light on solar system dynamics in the universe.  We've found many large planets that are very close to their stars in the hunt for exoplanets.  Perhaps these planets may one day migrate back away from their stars to sit in positions much like our gas giants do now.