As millions of Canadians sat down night after night to watch the Toronto Blue Jays in their march to the post season, they saw stars like Jose Bautista and Josh Donaldson — and they also repeatedly saw the face of Justin Trudeau in his party's election ads.

The confluence of the Jays' inspired late-season play and the valuable exposure for Trudeau owed itself to a decision made weeks earlier by the Liberals.

The party pre-bought significant airtime for election ads to run during Jays games, well before the team's run of victories that eventually saw it through two rounds of the playoffs.

The Liberal ad buy was as much a defensive move as an offensive one.

"There was an assumption that the Conservatives would buy all the available time because they knew the election timing and there was a concern we would get shut out," said a Liberal source, speaking on condition of anonymity. The source pointed to Conservative ad buys during the NHL playoffs right before the summer.

But one communications specialist says the Liberals were well-positioned to make that call.

Bill Walker, of Midtown PR, noted that Trudeau had some pretty big baseball fans among his senior campaign strategists, including principal adviser Gerry Butts and campaign director Katie Telford.

"They would have been saying, 'If [the Jays] keep playing the way they are playing, they could be playing in the Major League Baseball playoffs and imagine the audience for that,'" Walker told CBC News.

Big numbers

The payoff in terms of audience was huge.

The cable network that carried the games reported that the Blue Jays' playoffs delivered the highest ratings in its history. Sportsnet said Game 5 of the American League Division Series against the Texas Rangers, on Oct. 14, delivered an average audience of 4.88 million, for example.

That put millions of voters' eyeballs on the Liberal election ads for a bargain basement price. Sources told CBC News the Liberals paid a fraction — as little as one-fifth — of what a regular playoff ad would cost.

An ad based on footage from an Oct. 4 Justin Trudeau rally in Brampton, Ont. was one of the ads Blue Jays fans saw repeatedly in the days leading up to the Oct. 19 election. (CBC)

John Yorke, president of ad agency Rain43, agreed the Liberals probably got a significant discount for making an early commitment to the Blue Jays.

"The Blue Jays' success was not a surprise. This was all a part of an overall advertising plan, with only an upside. It was very clever," Yorke said.

The Conservatives also bought Jays ad time but purchased it later and at a much higher cost, sources told CBC News. On the Saturday before the Oct. 19 vote, the Tories launched a blitz of five ads. Sportsnet viewership for the Oct. 17 game between Toronto and Kansas City was 3.85 million.

But the Conservative ads focused on tying Trudeau to Ontario Premier Kathleen Wynne, targeting Ontario voters who may have been frustrated with Wynne's record. Walker said the Conservative ads were negative and that wasn't what baseball viewers wanted to see.

"People didn't necessarily buy what the Conservatives were selling with regard to Trudeau," Walker said.

By contrast, Walker believes the positive Trudeau ads helped build crucial momentum for the Liberals.

"I would venture to say, that if anything, the Blue Jays' success helped put the Liberals over the top in the terms of a majority government as far as advertising was concerned."