Over the years we have heard multiple NHL brass reference the natural rivalry a team in Seattle would have with Vancouver. I take a stab at quantifying the rivalry below by looking at the attendance for the Sounders and Mariners attendance when the Vancouver Whitecaps and Toronto Blue Jays are visiting Seattle.
It should be noted that the Sounders have opened up more capacity when the Whitecaps have come to town. They only do this a couple games a year when they know they can sell that additional capacity.
Toronto Blue Jays
Anyone that has been to a Toronto Blue Jays game against the Mariners knows the impact of Jays fans when they invade Safeco every year. This year, the Blue Jays-Mariners fell on a weekend and the series was the highest average attendance of a series since 2011. Below is the average attendance of each Mariner series since 2012.
As you can see, the most recent Toronto series had the highest attendance out of 95 unique series since 2012. The Blue Jays comparison is not perfect, it’s baseball, Canada has one MLB team, and it is one series a year.
One thing that is not known is how many people travel across the border vs. Canadians living in the area. I end up going with a few of my Canadian friends every year to experience the visiting fan impact on the game and I also have talked to several folks that travel down every year for the series. Again, this is not scientific but it does provide a leading indicator on what demand would look like when some of the more popular Canadian teams visit Seattle.