Jamie Roberts will sign a three-year deal with Harlequins provided Racing-Métro agree to release him according to reports.
The Wales and Lions centre still has one year remaining on his contract with the Top 14 giants, but is keen to join the Premiership side after a short spell doing a course at either Oxford or Cambridge in order to play in a Varsity match.
That would see Roberts head to Quins in December, with Racing apparently keen to offload his expensive contract from their books.
Dan Carter is already set for a move to Racing and he could be a potential option to replace Roberts at inside centre, while Rémi Lamerat is another possibility if he leaves Castres.
While there had been talk of a return to Wales, it seems that Roberts will instead try his hand in the Premiership, where he will provide some real quality in the centres for Quins, who have struggled to find an established pair in midfield.
If Roberts is released by Racing, he will be the second Welshman to leave the club early, following on from Dan Lydiate, who moved to the Ospreys midway through this season.
While the move has not been officially confirmed yet, it is expected to be completed within the next few days.