Jeff Gordon out of the No. 88 car for upcoming race at Michigan

Jeff Gordon will not drive the No. 88 Hendrick Motorsports Chevrolet next weekend at Michigan International Speedway.

Gordon, who is subbing for the injured Dale Earnhardt Jr. for the fourth straight NASCAR Sprint Cup Series race, told NBC Sports reporter Dustin Long at Bristol Motor Speedway that he has a previous commitment next weekend and will not be able to drive then.

A Gordon representative confirmed to Friday evening that Gordon won't race at Michigan.

But Gordon's absence does not necessarily mean Earnhardt will be back.

Alex Bowman filled in when Earnhardt missed the July 17th race at New Hampshire Motor Speedway because of concussion-related symptoms.

An official at Hendrick Motorsports confirmed that if Earnhardt isn't medically cleared to race at Michigan, Alex Bowman will be back in the No. 88.

Two weeks ago at Watkins Glen International, Earnhardt visited Watkins Glen and said he was continuing to rehab, but there was no definite timetable for his return.

"As soon as I can get healthy and get confident in how I feel and feel like I can drive a car and be great driving it then I want to drive," Earnhardt said. "I want to race. I miss the competition. I miss being here. I miss the people and as Rick (Hendrick, team owner) likes to say 'we've got unfinished business.' I'm not ready to stop racing. I'm not ready to quit.

"But, I'm not going to go in the car until the doctors clear me," Earnhardt said. "The doctors won't let me race. This is not my decision, but it's the right decision and I trust what my doctors are telling me. When they say I'm good to go I believe them. If they say I'm healthy and I can race I'm going to race."