Not only will the Scotland international striker have to start delivering the glut of goals the franchise is expecting from him, he must also earn the love of the Whitecaps fans, who still adored Hassli even though he had just two goals in 18 appearances this season.
Vancouver (8-6-7) announced Friday they had traded Hassli — one of their three designated players — to Toronto for a first-round selection in the 2014 MLS SuperDraft along with an international spot through the 2013 season.
But Miller is immune to pressure. After all, he is a rare commodity in international soccer being one of only five players since the Second World War to play for fierce Glasgow rivals Celtic and Rangers in the Scottish Premier League.
After a tough week on the training track, the 32-year-old is keen to have an immediate impact off the bench in Sunday's game against the best team in the MLS, San Jose (13-4-4), at BC Place Stadium.
So long as Miller — who was picked up from English Championship side Cardiff City — is given the chance from coach Martin Rennie.
"I'm feeling good so hopefully I get on at some point, we'll wait and see," said Miller.
"It's the coach's decision, but I want to get involved as soon as I can and get some match time under my belt. Obviously as a striker you want to get on and get a goal as soon as you can, but I'll just go out and play my game when I'm asked upon and we'll see what happens. I won't feel any extra pressure towards it to be honest."
Miller was in high spirits with his teammates on Saturday and is confident he made the right decision to leave the United Kingdom.
"It's a good vibe to the squad so I've fitted in pretty well," he said.
Rennie likes what he has seen of Miller so far and said the course of Sunday's game will determine if his new offensive weapon will make it onto the field.
"He looks very sharp, his finishing has been very good and his fitness is coming along," the coach said. "Obviously he's just starting to get fit because he's just started pre-season training really but he looks very good and he brings a lot to our team."
The sooner Miller regains peak match fitness, which he expects to achieve in the next two weeks, the better for the fourth-place Whitecaps.
Vancouver have only managed 23 goals this season. The visiting Earthquakes have struck a league-leading 43 times, with 17 of them coming off the lethal boot of Chris Wondolowski.
The Caps are winless in their past four games and squandered a 2-0 lead before drawing 2-2 with MLS Cup champions Los Angeles Galaxy at home Wednesday.
San Jose on the other hand have won their past two games, which included last weekend's 5-0 thrashing of the second-place Real Salt Lake.
And if pundits needed any more convincing as to why Frank Yallop's side is the best in the league, the Californians have also compiled a 6-3-2 record on the road.
Meanwhile, in a further boost to Vancouver's front line, striker Atiba Harris has recovered from knee surgery and could make his first appearance in a competitive game since May 2.
The versatile Alain Rochat will return from suspension and looks set to resume his regular spot at left-back after playing in that position in training.
But Rennie was keeping his cards close to his chest, hinting Jordan Harvey could hold onto his role in the back four.
"Jordan has done excellent in the games he's played so either one of those will do well for us," he said.
The last time the Whitecaps met the Earthquakes on May 5 was a memorable encounter, particularly for the home fans.
A last-minute strike from substitute Hassli handed the Caps a surprise 2-1 win.
Although the weeks have passed since then, Vancouver captain Jay DeMerit said the team can still take plenty of belief out of that game.
"Any time you beat a team like San Jose you can take those as major positives as you go on through a season," he said.