The Brazilian has been deemed surplus to requirements under Louis van Gaal, who preferred Antonio Valencia at right-back last season before signing Matteo Darmian from Torino this summer.
Rafael has been linked with a move to Turkey but it seems Lyon have won the race for the 25-year-old, with Aulas tweeting that the “cheerful Brazilian” has arrived in France to finalise a deal.
Aulas says the Ligue 1 side expect to reach an agreement with United, who similarly allowed Robin van Persie to travel to Fenerbahce before a fee had been agreed. Reports on Monday suggest an amount in the region of £2.1million will seal the deal.
Rafael has made 109 first-team appearances since joining the club from Fluminense in 2008 along with twin brother Fabio. The energetic right-back emerged as a fan favourite at Old Trafford under Sir Alex Ferguson but poor form under David Moyes and Van Gaal’s lack of trust has seen his stock fall dramatically.