Doctors narrowed down the likely cause of NASCAR driver Dale Earnhardt Jr.’s concussion to a crash on June 12 during the Sprint Cup race at Michigan. Today, his Hendrick Motorsports team that Jeff Gordon will continue to fill in for the next two races to allow Earnhardt to continue recovering.

Eanrhardt hasn’t been racing since July 9, but continues to address his recovery through social media, his Dirty Mo Radio podcast network and various public statements.

This week, he explained on Dirty Mo’s that this concussion has been particularly harrowing compared to his previous concussions, as it’s unusual for his symptoms to wait so long to appear:

Obviously with my history of concussions, knowing the event I had in Michigan, that wreck right there is where they believe I picked up this issue.

I didn’t feel anything that next week. The off week, I went to Germany (on vacation), went to Sonoma, ran good, felt awesome. It was strange to me that these symptoms came out of nowhere. I didn’t know what was wrong with me and why this came out of nowhere. But we started doing a lot of digging, and they seem to feel confident this occurred in Michigan.

I’ve never had a concussion that came on weeks after the event. Most of them you feel it immediately and they sort of get better over time. So this has been the opposite. This is scary for me because of the way it’s been different.

Here is that incident from Michigan, where Chris Buescher’s No. 34 car got loose, contacting the rear of the Earnhardt’s No. 88 car. Earnhardt’s car then collected the No. 47 of A.J. Allmendinger en route to the outside wall.

Earnhardt’s hit was a hard broad-side into the wall that bounced him back into the infield apron.

Of course, Earnhardt was involved in another hard hit at Daytona several weeks later, which didn’t help, either.

Doctors diagnosed Earnhardt with “gaze stability, affecting vision and physical balance,” writes . It has been three weeks since Earnhardt decided to get his condition checked out, and he told listeners on his podcast that he feels as if his recovery has plateaued somewhat. Some days are better, and others, he’s back to having issues again.

While it’s extremely difficult for Earnhardt to be patient, he says he’s doing everything doctors are asking of him in order to recover as fast as he can.

You can listen to the full podcast with the latest update on Dale’s condition .