It doesn't end there. The absence of this kind of star even draws questions about NASCAR in general, even though it has worked hard not to rely on Earnhardt -- the winner of the most popular driver award in each of the past 13 years -- as the sole face of the sport.
"Dale is definitely a leader in our sport," said Elliott Sadler, who drives for a team co-owned by Earnhardt in the Xfinity Series. "He is one of the good guys. He's one of the blue-collar guys, down-to-earth guys, the guy who tells it like it is.
"He is one of the true grit racers in our sport and always has been."
Earnhardt can continue to be a leader in the sport. Many have praised him for making the decision to get out of the car, but he will also point out he didn't feel there was any way he could race in the condition he's in. He also has, through social media, showed fans what some of his rehab entails.
For Earnhardt, he will have to balance any risks to coming back versus his desire to race. The emphatic answers he gave last month when asked about retirement -- bolstered by the resurgence in his career the past five years that has seemed to reinvigorate him -- show he desperately wants to race again.
His contract runs through next season, and he had talked about an extension with team owner Rick Hendrick. Many in the sport believed that extension would likely be Earnhardt's last, that he would race well into his mid-40s (he turns 42 in October) and then hang it up.
His team will work with a couple of drivers the remainder of the year. Four-time Sprint Cup champion Jeff Gordon will do four more races, including this weekend at Darlington. He will run at tracks he's traditionally strong at -- Richmond, Dover and Martinsville.
Alex Bowman will run the rest, giving the 23-year-old several opportunities to show what he can do and get comfortable in the car.
The team now goes into this stretch knowing it could win only what is called the owners championship. It really is a team title, and it means much more to teams than it does to the public. But the bonus money is the same to the team as it is for who wins the driver title.
Crew chief Greg Ives said the motivation for the Hendrick No. 88 team comes from wanting to run well. His team sits 15 points outside the final spot in the owner version of its Chase with two races left in the regular season.
"Every point I can get on the racetrack drives me," Ives said. "The pride is being able to finish races and get as many points as possible.
"The health of our driver is No. 1. ... To be able to strive through [some mechanical issues] and still be 15th in points and know we have to get a couple more to be able to ensure a potential owners championship, that drives us with a little bit of a spark."
Ives doesn't worry that his crew might want to leave if Earnhardt can't return. He said the atmosphere at Hendrick Motorsports -- where the Earnhardt and Jimmie Johnson teams share a shop -- creates more of a sense of working for the company than a specific driver.
"I don't think anybody is forecasting that far ahead," Ives said. "For me, I know I'm not. ... It's just one of those things where we keep going, keep working hard."
It's not just Earnhardt's Sprint Cup team that is affected. Other drivers, if they have concussions, will see what Earnhardt did and be encouraged to follow a similar path. But drivers with less secure sponsorship and rides still could feel pressure to race while injured.
Drivers know they compete in a dangerous sport. And despite how much work goes into safety, they tend to put a lot of their future up to fate.
"Time will tell," Joey Logano said about Earnhardt's return. "I'm not going to be the guy that's going to be able to answer that question for you.
"All I can say is he's in our thoughts and our prayers and either way God's got a plan for him and it will work out, but a lot of the time you don't know God's plan until it happens."
There also is the challenge for the sport in having its most popular driver absent.
Attendance and ratings don't seem to have been affected yet by his absence -- tracks with expected sluggish sales have been sluggish -- but now that fans know he won't be at their track, there certainly is at least mild concern throughout the sport.
The first track that comes to mind is Talladega, where ticket sales since Earnhardt's announcement have not shown an impact, according to a spokesman.
The elimination-style Chase format introduced in 2014 also has added drama to the final 10 weeks of the season.
"When Dale Jr. is the most popular driver in our sport and you don't show up to the track for two or three weeks, not that you are forgotten, but it's crazy how things move on," Jamie McMurray said.
"I don't know that any of us knew what to expect or how that was going to go, but I don't know how to say that and to be, like, correct. ... He is iconic and he is obviously the most popular guy, but it will move on and it will continue to be a great form of auto racing in the United States."