Larson and his teams — Arrow McLaren for IndyCar and Hendrick Motorsports for NASCAR — have backup drivers ready to go.

“I think you could look at the forecast and get worried now,” Larson said Thursday. “I have no answers for you guys, as far as decisions and all that. I don’t think anybody really does at this point. It just probably has to come down to game-time decisions and playing it by ear. … So hopefully, the weather gods work out for us, and we can get both races in.”

IndyCar officials have said they’ll do everything they can to get the Indy 500 in on Sunday, as it’s seldom postponed. So should Larson have to pull out, 2013 Indy 500 winner Tony Kanaan will be on the timing stand Sunday just in case, Arrow McLaren confirmed Thursday. Additionally, NASCAR driver Justin Allgaier will be on standby in case Larson isn’t able to make it to Charlotte, Fox Sports’ Bob Pockrass reported Friday.

“I’m the one behind the wheel, so I would think that I have some sort of play in logistics and all that and decisions. But again, I think it all just comes down to game time and figuring it all out on the spot. You have a plan. There’s backup plans for the backup plan and the backup plans for that plan, so you just don’t really know until it comes down to the moment.”

If IndyCar is unable to get the Indy 500 in on Sunday because of weather, the race will likely be pushed to Monday.

On the one side, it would increase the chance that Larson could compete in both events. On the other, it would probably lead to an asterisk next to his Double stats because he technically wouldn’t be doing them on the same day.

“I would love to be able to complete both races, whether that’s on separate days,” Larson said when asked about how much it means to just do the Indy 500 versus the impact of doing The Double.

“It’s The Double right, it? And is it truly The Double if it’s not on the same day? I don’t know. In a perfect world, I would love to have it all happen on the same day, to have done it. … Even if I got both races in, I would for sure probably be a little bit bummed that I wasn’t able to do both in the same day. But I think I would be happiest, though, if I did get to run both and didn’t have to, you know, come out of one car or whatever.”

The Indy 500 is a strenuous race regardless, and the same is true for the Coca-Cola 600, NASCAR’s longest race by 100 miles. Larson is an exceptionally versatile racer, so he’s often competing in multiple events between NASCAR races.

The Double is different, however, so Larson explained how he’s preparing physically for two monster races.

“I race so often that I stay pretty well in shape, but I have taken my training a little bit more serious the last couple years,” Larson said. “And then I just think to do The Double, you just have to stay ahead of your hydration and your sleep a little bit. So been trying to sleep a little bit more, and then stay on top of the hydration.

“We’ll have an IV lined up on the airplane, and hopefully all that will go smooth and be fine. So I feel like I’m as fit as anybody is in when it comes to racing. I look at other drivers and the shape that they look like they’re in after the race, and I don’t typically sweat much. So yeah, I feel like I’ll be OK on that front. But yeah, still got to stay ahead of it.”

The Memorial Day Double is a dream feat for so many racers, including Jeff Gordon, who’s now the vice chairman of Hendrick Motorsports. And Larson — who IndyCar driver Pato O’Ward described as a “guy [who] wants to drive anything that’s got four wheels” — has been thinking about it for a while. 

“I couldn’t put an exact date on it, but I’m sure when I was really young, I knew what The Double was,” Larson said. “And I think my love for driving lots of different types of vehicles made me kind of be intrigued about doing something that challenging. And then my goal was always to make it to the NASCAR Cup Series. But within that goal, I still wanted to compete in the Indy 500. So glad that it’s going to be able to become a reality and get to do something that only four other drivers have at this point.”

Defending Indy 500 winner Josef Newgarden — who wants to try The Double itself at some point in his career — hypothesized it’s easier to handle speeding up to an Indy car from a NASCAR stock car than it is to slow down vice versa.

But Larson explained that with significant support from both NASCAR and IndyCar teams, his adjustments have been fairly smooth.

“Thankfully, for me, this process has not been that difficult. And to that, I would say it’s because our Next-Gen cars are a lot more similar to an Indy car than what they used to be, so it it really doesn’t feel like I’ve had to adapt to a whole lot.

“As far as the driving goes, maybe just getting familiar with the cockpit. It’s been the most difficult thing and that’s fairly simple. I think just having good preparation too, good team to you lean on you having a guy like Tony Kanaan to talk to all that has been very beneficial, and it’s helped everything not feel so difficult.”

“An IndyCar at an oval,” he added, “it’s not too far different to me than than a NASCAR Cup Series car.”

Larson’s 6-year-old daughter, Audrey, shared with him this week that she thinks her dad will finish the Indy 500 second to 2016 Indy 500 champ Alexander Rossi, Larson’s Arrow McLaren teammate who used to drive for Andretti Global.

“We’ve been filming this documentary thing that’s been following me around for months now, but they were kind of having fun with the kids [Wednesday] night, interviewing them, so to speak,” Larson explained. “And I think one of the questions to Audrey was like,’Who do you want to win?’ or something. And she didn’t say me.

“She said I would finish second. So they were like, ‘Well, who’s gonna win?’ And she said, ‘Alexander Rossi.’ So she must be a Rossi fan. I don’t know how she got it, but she had one of his old Andretti kind of Jersey things for a couple years now, and so maybe that’s why she was a big fan of his.”