It's hard to wipe the smile off Colin Miller's face these days.Just over a year ago, Miller left his dual head-coaching roles with the Abbotsford Soccer Association and the UFV Cascades women's program in favour of an assistant coaching gig with the Vancouver Whitecaps men. It was a decision that Miller termed "difficult" at the time, given his roots in the Abbotsford community. But a big part of the payoff comes this Saturday, as the Whitecaps make their Major League Soccer (MLS) debut against Toronto FC (3:30 p.m., Empire Field). "I'm at the highest level of club soccer in North America now, and it's a privilege to be a part of it," Miller told The News earlier this week. "I've worked very hard, paid my dues to get to this level, both here in Canada and in Scotland as a player and a manager. I'm very fortunate to be where I am at the moment. Every day has blue sky."I'm really enjoying my job, no question about it."Working under Whitecaps head coach Teitur Thordarson, Miller deals primarily with defensive matters. "There are days where we'll split the group up and I'll look after the back four," he said. "That's a tremendous compliment that Teitur trusts me to do that."The Whitecaps, who are moving up from the USSF Division 2 to MLS, boast a nice mix of veterans and youth. Miller believes they have what it takes to contend for a playoff berth in the top league right away."We've competed very well against MLS teams in friendlies," he pointed out. "By no means are we out of our depth. Having said that, we realize we will have to be at our best and finish our chances when we get them. Our goal, for sure, has to be to make the playoffs and be as successful as we can be."Miller believes the Whitecaps' move to MLS has the potential to ignite the popularity of soccer in the province."It is a very, very exciting time for the sport," he said. "It takes me back to my days growing up in Vancouver, when the Whitecaps were playing in the old North American Soccer League. You can really sense the excitement building up in the city."There's going to be kids who will be coming through the various High Performance League teams in B.C. who will say, 'One day, I want to play for the Whitecaps.' We have to be the figurehead, the example that young players want to aspire to. And I think we're capable of doing that."