The 19-year-old central defender, who hails from Mitchell’s Plain in Cape Town, has been on the South African radar for some time, after having been named 'Player of the Tournament' at the Metropolitan Cup in 2011.
He received further recognition in the National Engen Tournament where he was named 'Defender of the Tournament', and subsequently offers to secure his services were made by several PSL clubs.
The ASD academy also produced Ayanda Patosi, who now plays for Lokeren in Belgium, and national Under-20 winger Ebrahim Seedat.
ASD Director Mike Steptoe says: "Ethen is the consummate professional – since the age of 17 he's had some of the top SA clubs trying to turn his head with the offer of contracts, but Ethen knew he still needed time to develop his game if he were to make it overseas.
“To his credit, he has been remarkably patient in his pursuit of a professional contract, which isn't always easy when teammates are moving on. His family have been incredibly supportive too, his father Victor in particular, and we are all thrilled that Ethen's hard graft has finally resulted in a contract.
“Ethen trialled with the Whitecaps late last year. They have a great set-up and we are confident Ethen will continue to develop under head coach Martin Rennie's care and guidance.”
Sampson has been offered a two-year contract, and is set to join his new teamamtes for pre-season in the next week or so.
"I loved my time on trial in Vancouver – their training sessions were really similar to the training we do at ASD, so it felt like I fitted in straight away,” the player says.
“I know this is a great opportunity for me and its what I have been striving for. I really hope my move will open more doors for ASD players in the MLS, because ASD has not only made me the player I am today, but also also the character I am both on and off the field.”
The Vancouver Whitecaps became the first Canadian team to qualify for the MLS Cup Play-offs last year. They were defeated by then-defending champions LA Galaxy, but have been building upon the experience and look set to be a competitive outfit in the 2013 season.