He didn't want to reflect on everything he had accomplished in his first pro season and didn't want to look forward to how he might be able to top it in his first full NHL season.
But once he had his rest and was mentally prepared to do it, Subban looked back to those tremendous playoff experiences with the Canadiens, to beating the mighty Washington Capitals and Pittsburgh Penguins in Game 7 situations -- and he liked what he saw.
"I watched game tape all summer once I got bored," Subban said. "I watched that Game 7 against Washington, and when you watch that and see all the emotion, you realize that was a pretty good game. Those are big games that we were playing, and to see the plays we were making in those big games -- it gives you confidence."
It would be hard to imagine Subban would need any more of that.
The 21-year-old Toronto native who grew up loving the Canadiens in enemy territory has oozed confidence from the day Montreal selected him with the 43rd pick in the 2007 Entry Draft.
Subban walked up to then-general manager Bob Gainey after the announcement of his selection, and promised his new boss that he would one day be happy he drafted him.
That day has arrived, as Subban is getting ready to make a charge for the Calder Trophy in his rookie season for the Canadiens -- one in which he should have plenty of opportunities to show his dazzling array of offensive skills.
But that toolbox was never in doubt. What Subban was sent to Hamilton last season to learn was how to play in his own end, how to play without the puck, how to pick his spots.
Basically, he was sent to learn how to play for Canadiens coach Jacques Martin.
A year later, it is clear that the two will have to learn to co-exist, because Subban's high-risk, high-reward style is the type of thing that tends to give Martin more gray hairs.
It's a fine line that Subban needs to walk -- he won't be effective if he plays a conservative game, but Martin is not likely to have much patience if Subban's defensive failings cost the Canadiens more goals that his skills can generate.
"Right now I'm trying not to think about the line," Subban said during training camp. "I'm just trying to go out and play and get back into the mindset I had last season. Whatever comes to mind, I'll do it. As time goes on I'll make those corrections."
Martin is already thinking about that line, and it's clear what side of it he wants Subban to find himself on more often than not: the safe side.
"P.K. has some good qualities with the puck," Martin said. "But he has to find a happy medium in terms of when to support the attack and when to focus on defense."
PK Subban (Gety Images)
He was just as crucial in the second round, filling the big skates of injured star Andrei Markov. Subban's ice time climbed well north of the 20-minute mark every night, and he helped lead Montreal to another unlikely seven-game upset of Pittsburgh.
But the dynamic there was different in that Subban was entering a situation that was already clearly defined, and he just tried to fit in.
Having a full season within the group should give Subban a little more latitude to try some things, but he insists he doesn't want to look too far ahead before it's even official that he's made the team -- even though there is absolutely no way Martin would cut Subban, risks or no risks.
"It's good for your confidence, but you can't get too carried away with it," Subban said after scoring a goal in his first game of the preseason Friday night, helping the Canadiens beat Ottawa 4-2. "You've got to continue to do the right things, keep the game simple, try not to do too much and know when to try the little moves you have and using your skill set. But for the most part you've got to play within the team system."
Words like that will be music to Martin's ears. But now it's time to see if Subban can stick to them.