EDMONTON — Like Mike Tyson so famously said, everyone has a plan — until you get punched in the mouth. Or get a lower-body injury.

After a training camp spent centring the Edmonton Oilers’ second line, Ryan Nugent-Hopkins will miss Opening Night on Tuesday with a lower-body injury believed to have been suffered at practice Monday. Losing Nugent-Hopkins will likely force head coach Mike Babcock to blow up his top six.

Connor McDavid and Leon Draisaitl, who spent the entire training camp on the top unit together, will likely centre separate lines against the Vancouver Canucks in the season opener for both teams.

“Anytime someone leaves practice, you always get a little bit nervous,” new Oilers coach Mike Babcock said of losing the versatile Nugent-Hopkins. “It took me a couple hours to bounce back, but we’re all good here. Let’s get after it.”

How much time is Nugent-Hopkins expected to miss?

“Any time they tell me day-to-day, that usually means two weeks, is what I go by,” said Babcock, who enters his first regular season behind the Oilers’ bench missing five regulars.

Babcock gave an injury update Tuesday morning:

“When I watch Dicky (Jason Dickenson), he hasn’t been able to push it yet. So that means you’re a bit away. Savvy (Matt Savoie), I think the start of the week he was eight weeks away, so …

“Freddie (goalie Frederik Andersen), I think maybe December. And Janny (Mattias Janmark), I don’t know this one. He’s a ways away.”

Fourth-line winger Max Jones will draw in for Nugent-Hopkins, likely manning a line with rookie Owen Michaels and Trent Frederic.

Babcock did not lay out his lines before an optional practice, but we’d expect McDavid to centre Zach Hyman and Ike Howard, with Draisaitl between Vasily Podkolzin and Kasperi Kapanen. That leaves a fourth line of Colton Dach between Mathieu Joseph and Alex Formenton as the only training camp line to survive unchanged.

“That’s just the way injuries unfolded. Just the way it is,” shrugged McDavid. “There are going to be guys asked to do certain things, put in different spots, and that’s the nature of this business. It’s a long season. It’s obviously Day 1, but these things happen throughout the course of the season and we just adjust as we go.”

Losing a quarter of your 20-man starting lineup before Opening Day throws a wrench into a team that’s learning a new system under a new coach, with new line combos a completely different penalty-killing strategy.

It’s hard to build when you’re missing so many blocks.

“You can look at it that way, or you can say it’s (an) opportunity for other people,” countered Babcock. “I’m just going to watch, and they’re going to decide (who plays where). We might find a penalty killer. We might find a power-play guy. That’s what happens when these things go on.

“You think you don’t have somebody, and then suddenly you’ve got somebody you didn’t even know you had.”

If you’re looking for a bright side, these injuries should focus the Oilers. A team with only one thing left to prove — winning the Stanley Cup nine months from now — has no choice now but to say in the moment.

“That’s something that we’ve talked about a lot,” McDavid said. “It’s just about going through those checkmarks. Going through the captain’s skates, get through training camp, pre-season. … I feel like we’ve done as good a job as we could have.

“Here we are in the regular season, and we want to get off to a good start, and that’s part of the list. So you’ve got to go through the process of the season, and here we are at the start of that.”