Sean said of the former Cambuslang RFC stand-off: "We've been watching Duncan for a while now. He is a talented youngster with an outstanding kicking game. I really like his attitude and I'm looking forward to working with him."
The signing of Duncan follows on from the acquisition of Heriot's flanker Chris Fusaro and Warriors chief executive, Kenny Baillie, today expressed his delight at seeing yet more young Scottish talent emerging from the Scottish club scene.
"I strongly believe there are a lot of very good rugby players within the club game in Scotland, and in Chris and Duncan, the Warriors are fortunate to have secured the signatures of two of the most promising young players to come out of the club game for many years," Baillie said.
"At the same time, this is an excellent club for them to join as the attention to detail of all the coaches and support staff is off the highest standard and the boys will receive the very best in coaching and player welfare.
"Along with all the Warriors fans, I am excited about watching both players play in and win matches for the club in the years to come."