"We wanted to use the second power unit this weekend, but a quality problem means we've moved it to the French grand prix", a spokesman is quoted as saying by the German media.
And the race in Canada will have the same compounds that were used in Monaco - the supersoft, the ultrasoft and the hypersoft tires - when Mercedes struggled to bring it up to the optimum temperature and extract the maximum performance from the tires.
"So all Mercedes-powered cars will be running PU1 for this weekend, too, before receiving new units in France".
Asked about Ferrari's engine upgrade for Canada, which debuted in the back of the Haas and Sauber in Monaco, Vettel added: "It's always been the plan, so let's see".
"There are tracks where each driver has strengths and weaknesses", Hamilton said.
"I've never driven the circuit in Montreal so I'm looking forward to driving there", said the Russian.
Stroll has only four points through the first six races from an eighth-place finish in Azerbaijan.
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Ferrari are also expected to use an upgraded engine for all their teams, but this has not yet been officially confirmed.
Mercedes will come to the Canadian Grand Prix as favorites with the team having dominated the last few of seasons.
The big loser could well be McLaren who have been the slowest in a straight line throughout this year and are unlikely to make up that deficit in other areas.
Both Toro Rosso drivers, Pierre Gasly and Brendon Hartley, will have an upgraded Honda engine.
Southern Ontario last hosted the Grand Prix in 1977, when Bowmanville Ontario's Mosport Park was the site for the F1 auto race.
For the team, it is hard to look beyond Ferrari as they hold so many aces up their sleeve heading into the weekend.
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