Douglas has been at Netherdale since 2002

And back-row forward Kelly Brown has also agreed a new two-year contract at Netherdale.

Douglas, 26, said: "I have spoken with Frank Hadden and I have decided that, in the build-up for the World Cup, it's best for me to play in Scotland.

"Teaming up with Ross Ford and Gavin Kerr next season will give us a pretty impressive front row."

Douglas joined the Reivers from Harlequins in 2002 and made his first Scotland appearance in the November Test against Romania that year, and now has 41 caps to his name.