Earnhardt, Jr believes concussion happened at Michigan UPDATE:

#88- Dale Earnhardt Jr. said his doctors believe his concussion-like symptoms started with his June 12 crash at Michigan International Speedway. ‘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,’ Earnhardt said Monday night on his weekly Dale Jr. Download podcast. ‘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 these symptoms came out of nowhere. But we started doing a lot of digging, and they seem to feel confident this occurred in Michigan.’
‘This is scary for me because of the way it’s been different. I’m having balance issues. I’ve never had balance issues before. The eye issues with the stability, I’ve never had that before. It started very slowly, gradually and continued to progress until it stopped and stayed where it is. I don’t know what tells me about how long this process is going to be. I felt I had a good understanding of concussions in the past, but this is certainly a new one. They all have different symptoms and own time and length of recovery is different.’(NBC Sports)(8-2-2016)
UPDATE: Dale Earnhardt Jr., driver of the #88 Chevy for Hendrick Motorsports, has not been cleared by physicians to compete in at least the next two NASCAR Sprint Cup Series events as he continues to recover from a concussion. He will miss the races at Watkins Glen International (Aug. 7) and Bristol Motor Speedway (Aug. 20). Earnhardt underwent further evaluation today at the University of Pittsburgh Medical Center Sports Medicine Concussion Program. The driver said Monday on his weekly ‘The Dale Jr. Download’ podcast that he continues to experience issues with balance and gaze stabilization. ‘We have a break in the schedule after Watkins Glen, so the extra week of recovery time will certainly be a benefit,’ said Rick Hendrick, owner of Hendrick Motorsports. ‘Dale will be back when he’s ready, and we’re looking forward to that happening, but the priority continues to be his health and well-being. We’ll keep our focus on that and let the doctors guide us.’ Jeff Gordon will be the team’s substitute driver at the Watkins Glen road course, where he will make his 800th career NASCAR Cup start, and Bristol. He is NASCAR’s all-time leader with nine road course victories, including four at Watkins Glen. The four-time series champion, who has five wins at Bristol, has made all 799 of his career Cup starts while driving for car owner Hendrick.(HMS)