We'll begin to find out tonight, as the puck drops on Game 1 in Boston (7 pm ET on CBC/Sportsnet). It was also a move Toronto's goalie might not have even attempted a month ago.
The most telling sign that Frederik Andersen is tuned into his game is when he's tuning out the fans, the critics and all the white noise around him.
What impressed me the most about Toronto on Thursday was how much the John Tavares line dominated the Bergeron line, and how well Frederick Andersen played. During those wobbles where his save percentage sat at just.874, he was often caught chasing the play, guessing what was coming next instead of using his instincts to react.
Teenage defenseman Miro Heiskanen built on his stellar rookie season in his playoff debut with Dallas, 19-year-old Andrei Svechnikov tried to carry Carolina back from a big deficit, early 20-somethings Mitch Marner and William Nylander continue to be among Toronto's best players and young Matthew Tkachuk did his part to finally win a playoff game with the Calgary Flames.
But with the clock ticking down towards the playoffs, it was a matter of "when".
"Listen, you want your goalie to stop everything", said Cassidy.
Outside of the Marcus Johansson, Charlie Coyle and Danton Heinen trio, there were very few bright spots for the Bruins in Game 1. The Toronto Maple Leafs are averaging four goals per game and are scoring on zero percent of their power play opportunities. Yeah, we would have liked the penalty shot save.
"You just work through it", Andersen said of those March struggles that started to evaporate once the calendar flipped to April. We've been exposed by them on those breakaways and you give up two, three in a row that period, so shame on us. You learn from it and you keep pushing.
"Sometimes the puck's not following you".
Somewhat surprisingly given their playoff history and the notion they were favourites to win the series (and still could be), the Bruins were flat from the opening faceoff, though the Leafs' tireless effort influenced anything the Bruins did on each shift.
"He was a rock back there for us", defenceman Jake Muzzin said. What surprised me about game one was how ineffective the Bruins were when they had a 5-on5 situation on the ice.
"They'll come out twice as hard", said Muzzin. "For us four just making sure were trying to play as hard as we can down in their zone, make it hard to get out, when they do get out we're fully fresh".
"He's pretty good at staying steady with his mindset", Leafs winger Connor Brown added. "We weren't doing him a lot of favours down the stretch (in the regular season)".
The Leafs had their doors blown off in the first two games in Boston last spring, getting outscored 12-4 in falling behind 2-0 in the series.
Facing off at home against one of their longtime rivals, the Toronto Maple Leafs, the Bruins were thoroughly defeated by the Leafs with a final score of 4-1. Moot now, we suppose, but the Leafs will have to at least match their own intensity in Game 2 ... The Bruins outshot Toronto 21-14 in the second period, but gave up two goals.
"We need to elevate our game again", Leafs centre Auston Matthews said.