Wales' midfield injury troubles would deepen considerably if anything happens to the 55 times-capped Roberts.
The former Cardiff Blues centre is back in Paris with his Wales and Racing Metro teammates Mike Phillips and Dan Lydiate, and he looks set to be involved in tomorrow's Top 14 game against Bayonne.
Wales host France next Friday, having lost centre Scott Williams from their plans due to a shoulder injury, while Williams' Scarlets colleague Jonathan Davies has played only 40 minutes of rugby since early November.
With Williams sidelined and British and Irish Lions player Davies battling to regain full fitness after a torn pectoral muscle, Wales head coach Warren Gatland seemingly faces a choice of James Hook, Ashley Beck or wing George North as Roberts' midfield partner against Les Bleus.
Wales must beat France at the Millennium Stadium to retain any realistic hope of being crowned RBS 6 Nations champions for an unprecedented third successive season.