"I don't think it was actually swine flu," he said. "But it felt like swine flu. Very similar. Very awful."
As the Bruins went through China during the preseason, with games in Shenzhen and Beijing, everything was going through their 21-year-old winger. "We went on a three-and-a-half-hour bus ride to the airport and then a flight for 12 hours after that. That was tough."
Inconsistency, it seems, was already plaguing DeBrusk.
He was impressive in stretches last season, with 16 goals and 27 assists in 70 games, playing big minutes with center David Krejci on the team's second line. He managed 143 shots on goal, fifth among Bruins forwards, and picked up a few votes for the Calder Trophy. But he was a rookie, and with that inexperience came bumps in the road, such as his one assist in six games and five games without a point.
The role DeBrusk is playing for the Bruins this season is a critical one. His performance as the second-line winger could influence everything from lineup decisions to whether GM Don Sweeney feels the need to go shopping for another winger, as he did in acquiring Rick Nash last season. As DeBrusk's sophomore campaign gets rolling, it's that dependability that coach Bruce Cassidy needs to see.
"What we're looking for is a little more consistency on the nights when the offense isn't there," he told ESPN last week.
"Saying that young guys disappear is maybe a little unfair. But sometimes they're not as dialed in as they need to be. Mentally, they're not as strong as the older guys, who know there are going to be rainy days. Some rainy weeks and months. So you just have to find a way to contribute. That's what happens with the younger guys. They have a level of success, and that's what they want every night, but life doesn't work that way."
DeBrusk knows this. That's why he has sought council on how to handle what he has called "some ups and downs" in his first NHL season. "I listen to the veterans here. [Krejci] was helping me out, saying stuff that he went through. Obviously, he's played for a while. He understands the game," DeBrusk said.
"And, of course, my dad."
Having a father who played in the NHL, which Louie DeBrusk did for 401 games from 1991 to 2003, has its advantages. Those included growing up in "the life," whether it was hanging around the dressing room or simply being a fixture in an NHL arena, as Jake DeBrusk was during Louie's time with the Phoenix Coyotes as a broadcaster. When the Bruins played in Arizona last season, some of the arena personnel still remembered him as the little kid skating around the ice after practices.
Another advantage is that Louis DeBrusk was a 21-year-old winger once, too. The sage advice he gave his son about consistency: Don't get discouraged by the numbers, and build on the little things.
"There's a difference between a guy that's playing poorly and a guy that's in a slump. We watch a lot of hockey. We see guys that stop playing, like they aren't backchecking. So you want to see effort," said DeBrusk, now a commentator for Sportsnet.
It might seem like a hockey cliché -- "Just play your game, and go have fun out there" -- but Jake DeBrusk has treated it like a mantra.
"It's kind of amazing when you take a deep breath and start playing, get some bounces here and there and get on the upswing," he said. "Stick with your guns. Stick with what got you here."
The fatherly advice doesn't just cover what happens on the ice.
In 2017-18, there was speculation that Jake DeBrusk wasn't long for the Bruins. In particular, there were rumors that the New York Rangers coveted him and that DeBrusk could end up in a package for someone such as defenseman Ryan McDonagh, who was eventually traded to Tampa Bay, or Nash, who ended up with Boston at the deadline.
"It is what it is. You can't control it," DeBrusk said at the time. "I love being with these guys, and we're a pretty tight group."
His father was also on the trade block as a young player. In October 1991, Louie DeBrusk was on the cusp of making his NHL debut with the New York Rangers as a highly regarded prospect in their system.
"And then I was traded for Mark Messier," he said.
DeBrusk was part of the three-player package sent from the Rangers to the Edmonton Oilers for Messier. (The rest, as they say, is history.) The shock of his change in trajectory subsided eventually.
His advice to Jake, when the two talked about those trade rumors last season? "Consider it an honor that another team thinks of you like that," he said.
When he remained a Bruin, Louie said, it was validation that Boston also valued him.
As Jake DeBrusk values being a Bruin.
He's a self-professed hockey nerd, which is a natural extension of a childhood brought up in the game. Playing for the Boston Bruins is, in some ways, a hockey nerd's dream. "The amount of history. The stalls. The rink. The city. Me being the hockey nerd that I am, I still get goosebumps," DeBrusk said.
There are few locker rooms in hockey where, on a given day, you can walk in and see Bobby Orr.
"He came in on an off day. Just chilling in the room, having a casual chat," said DeBrusk, who was star-struck.
Whether DeBrusk fills a prominent role with this franchise he adores depends on a number of factors, from his own play on the second line to the competition for that spot from other young Bruins on the roster such as Ryan Donato and Anders Bjork.
"He knows, he knows. But that competition can be a good thing for a young player," Louis DeBrusk said.
It's entirely possible that DeBrusk could hear his name come up again in trade rumors this season -- it has already bubbled up in chatter about Columbus Blue Jackets star Artemi Panarin -- but it isn't something he's dreading at the moment.
"The pressure's what I put on myself," he said. "Looking ahead, the trade deadline ... I haven't even thought about that. We're all in high spirits now. We're all confident in our abilities."
Before the Bruins' first game of the season in Washington, someone asked DeBrusk if scoring 20 goals was a reasonable bar for him to clear this season.
"We'll see, I guess. I'm a pretty confident person," he said. "I'm not going to say yes or no to that.
"The main thing is to build on last year. Every statistic, every aspect of my game overall ... I learned a lot last year. Had some ups and downs. Hopefully those ups and downs last year help me stay consistent."