The 31-year old has been brought in by Reds head coach Paul Mariner in a trade which sees a first round draft selection in the 2014 MLS SuperDraft head to Vancouver.
Mariner was thrilled to make the signing of Hassli who will provide great cover for the injured Danny Koevermans.
"I thought privately my world caved in because how do you replace a player of that quality?" said Mariner about Koevermans.
"I was pleasantly surprised to find out we could get this young man beside me. I can't tell you how elated I was we were able to get Eric."
And Hassli was also delighted to be starting afresh at a new club after often finding himself on the Whitecaps bench under Martin Rennie this season.
"I am a soccer player, I need to play," Hassli said. "I can't stay on the bench.
"Getting traded may be hard sometimes but I spoke with the coach and I felt so much appreciation.
"He really wanted me. I really want to work really hard to give back the confidence that he has."