(NASCAR) Dale Earnhardt Jr. will not be behind the wheel of the No. 88 Hendrick Motorsports Chevrolet for the next two NASCAR Sprint Cup Series races, including this weekend’s event at Michigan International Speedway, according to a Wednesday news release from Hendrick Motorsports.

Earnhardt did not receive medical clearance to return to NASCAR Sprint Cup Series competition, according to the team. He will be replaced this weekend in the No. 88 driver’s seat by Alex Bowman, who drives part time for the Earnhardt-owned JR Motorsports team in the NASCAR XFINITY Series, and next weekend at Darlington Raceway by four-time series champ Jeff Gordon.

“We know how hard Dale is working to get back,” team owner Rick Hendrick said in a press release. “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.”

Earnhardt has been sidelined by concussion-related symptoms for the last five NASCAR Sprint Cup Series races. The two-time Daytona 500 winner has been keeping fans updated on his progress in recent weeks via social media and “The Dale Jr. Download” on Dirty Mo Radio.

The Sprint Cup Series makes its second visit of the season to Michigan International Speedway this weekend, which culminates with Sunday’s Pure Michigan 400 (2 p.m. ET, NBCSN, MRN, SiriusXM NASCAR Radio). Earnhardt said that the effects of a crash June 12 in the most recent Michigan race played a factor in his current concussion-related ailment.

Gordon, interim driver of the No. 88 for the last four races, indicated last weekend that should an Earnhardt replacement be needed this weekend, a previous engagement would keep him out of the driver’s seat. Bowman, 23, subbed in at New Hampshire Motor Speedway last month for the first race of Earnhardt’s absence, finishing 26th after a late-race crash knocked him from the fringes of the top 10.

Gordon is a seven-time winner at Darlington and will pilot the retro No. 88 Chevrolet, which honors the “Gray Ghost” paint scheme of Buddy Baker.