The switch would have delivered a welcome boost thanks to the Circuit Gilles Villeneuve being a power-critical track.
The 2.709-mile (4.361-kilometer) circuit is as much a fan favorite as it is a driver favorite.
Haas driver Kevin Magnussen, of Denmark, comes through the hairpin during the first practice session at the Canadian Grand Prix auto race Friday, June 8, 2018, in Montreal. He leads Vettel by 14 points.
It's a defeat that sticks in the craw of Mercedes and team principal Wolff, who is determined the champion team will not repeat the same error again.
Daniel Ricciardo famously grabbed his maiden win at the 2014 running of the event after both Mercedes cars were slowed by an MGU-K failure. While Nico Rosberg managed to hold onto to P2, Mercedes were afraid Hamilton's brake problem would show itself on Rosberg's vehicle.
The "Senna S" opens the lap with a small right kink leading into a heavy braking zone at Turn 1, a tight left-hander that immediately opens into an arcing right-hander, with the imposing grandstands giving the complex a stadium feel. Stroll has only four points through the first six races from an eighth-place finish in Azerbaijan.
Along with his 2007 and 2017 triumphs, Hamilton has also taken top spot in 2010, 2012, 2015 and 2016. Aside from an awesome P20 to P9 run by Toro Rosso's Carlos Sainz Jr., there was drama until the very end out front.
Kimi Raikkonen (2005) and Kimi Raikkonen (2006) were both victorious prior to Hamilton's arrival on the scene, while Sebastian Vettel succeeded for Red Bull in 2013. While Hamilton won, the race pace of Ferrari made some believe that Mercedes weren't unbeatable.
Lewis Hamilton is concerned he won't be able to fight for victory at this weekend's Canadian Grand Prix after learning a planned engine upgrade has been delayed until the French Grand Prix. Ferrari ought to know Montreal by now, seeing as how the city has hosted every Canadian Grand Prix for the last 40 years.
An opening lap crash at turn three involving three cars brought out the only safety vehicle of the race, but otherwise, the race was as straightforward a race as it could be for Hamilton and Mercedes.