CONCORD, N.C. - Hendrick Motorsports announced Wednesday that Dale Earnhardt, Jr. will miss the next two races on the NASCAR Sprint Cup Series schedule after not being cleared by doctors as he continues to recover from a concussion.

Earnhardt will miss the races at Michigan International Speedway this Sunday and the Southern 500 at Darlington Raceway on September 4. The two-time Daytona 500 champion underwent further evaluation Wednesday at the University of Pittsburg Medical Center Sports Medicine Concussion Program.

Alex Bowman will drive the No. 88 at Michigan. Four-time NASCAR champion Jeff Gordon will return to the seat of HMS at Darlington. A prior commitment kept Gordon from remaining in the car at Michigan.

"We know how hard Dale is working to get back," said team owner Rick Hendrick. "He's following what the doctors are saying, to the letter, and doing exactly what he needs to do. Everyone wants to see him in a race car, but his health is first and foremost. We're behind him."

Bowman filled in for Earnhardt at New Hampshire Motor Speedway on July 17, where he finished 26th. He has four career Sprint Cup starts at Michigan with a best-finish of 26th in 2014. 

Gordon has seven career victories at Darlington, including six Southern 500s. His last win at the track "Too Tough to Tame" came during the 2007 season.