CHARLOTTE, N.C. — Dale Earnhardt Jr. will miss the rest of the NASCAR season — 18 races total — as he continues to recover from a concussion.

NASCAR’s most popular driver first began experiencing concussion-like symptoms in late July. He has been undergoing treatment from Dr. Micky Collins at the University of Pittsburgh Medical Center Sports Medicine Concussion Program. He’s also being treated by Charlotte neurosurgeon Dr. Jerry Petty.

“To say I’m disappointed doesn’t begin to describe how I feel, but I know this is the right thing for my long-term health and career,” Earnhardt said in a statement Friday. “I’m 100 percent focused on my recovery, and I will continue to follow everything the doctors tell me.”

Earnhardt said doctors have seen progress in his recovery, and he plans to be back in the car next February for the season-opening Daytona 500.

Joey Logano said he understands how difficult this choice was to make for Earnhardt.

“I look up to him for what he’s doing. I know how hard that is to look out and want to be inside that racecar,” Logano said. “Your life and your health is not worth risking for the sport.”

Elliott Sadler, who drives for Earnhardt’s Xfinity program, said he had mixed feelings about his friend’s absence. He knows how desperately Earnhardt wanted to return this season.

“The flip side is I’m happy and proud of him to take a step back and get everything in line from the medical side,” Sadler said.

Jeff Gordon and Alex Bowman will continue to share seat time in the No. 88 Chevrolet for Hendrick Motorsports. Gordon will drive four races, including Sunday at Darlington Raceway for the Southern 500, as well as Richmond, Dover and Martinsville. Bowman will finish the year with eight more starts.

“Jeff and Alex will give us a great opportunity over the rest of the season,” team owner Rick Hendrick said. “Jeff is one of the best of all time and knows our system. He brings things to the table that no one else can. Alex is a young driver with a lot of talent, and he will give us a fresh perspective. We know they’re not only capable of running up front and giving us a chance to win, but they’ll help us get better.”

Jamie McMurray said those in the Sprint Cup garage miss having Earnhardt around, but the sport will continue to thrive no matter how long he may be out.

“You don’t show up at the track for two or three weeks, not that you’re forgotten, but it’s crazy how things move on,” he said.

Earnhardt has struggled with concussions before, including the 2012 season when he missed two races after suffering a pair of concussions over a six-week span.

NASCAR has been updating its focus on concussions and treatment programs, beginning in 2002 in part because Earnhardt admitted he was unable to fully concentrate or communicate with his crew chief after an accident at California. He self-diagnosed himself with a concussion, which he revealed weeks later.

NASCAR then said doctors at infield care centers could require drivers to undergo CT scans or MRIs if they suspected a concussion. Clearance to race after suffering a concussion is not given until after a driver obtains a medical release.

More than a decade later, Earnhardt also spurred a baseline testing program that is now required of all drivers every preseason.

“I know how hard Dale has worked and how frustrating this is for him,” Hendrick said. “”He wants to be back, and we want him back, but we want it to be for the long haul. We’ve had incredible support from everyone involved with the team, including all of our sponsors. They’ve put Dale’s health first every step of the way.”