"We know how hard Dale is working to get back," team owner Rick Hendrick said in a statement Wednesday. "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, 41, has said his biggest issue is his gaze stability -- the ability to focus on an object at a distance while moving his head and not feeling off-balance or nauseated. Part of his rehab includes walking backward while moving his head in a dark room with disco lights, various basketball-type drills and an online 3D program that forces his eyes to work together.
"I don't know how long it's going to take," Earnhardt said Aug. 5. "As impatient as I am, I worry about everyone else's patience as well. But I'm not going to go in the car until the doctors clear me.
"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."
Earnhardt's doctors believe he suffered a concussion June 12 at Michigan but didn't start feeling the effects until four weeks later. He is being treated by doctors at the University of Pittsburgh Medical Center Sports Medicine Concussion Program. He visited them Wednesday.
"Dale looks great," Hendrick said Saturday. "I had lunch with him and the road crew [last] Wednesday, and you've seen him playing basketball.
"We're taking extra effort with the doctors making sure he's going to be 100 percent. ... He's coming along great, and he wants to get back in the car."
Bowman, 23, ran well before being involved in an accident and finishing 26th in the July 17 race at New Hampshire Motor Speedway, the first race Earnhardt sat out because of balance and vision problems.
Gordon, a four-time Sprint Cup champion, has competed in the last four races, and he said last week a previous commitment would keep him out of the seat this week at Michigan. He retired after the 2015 season and joined the Fox broadcast team, which has the first half of the Cup schedule, and had planned to come only to select races over the second half of the season.
"I was enjoying my summer a lot," Gordon said last week. "To go from my experience [vacationing] in France and how relaxing that was to the intensity level at Indy, it was a big wakeup call for me.
"Every week that I'm in the car, I get more comfortable, and I get in a place where I feel I can contribute more and ramp my intensity level up along with the competition. You can't just be out of it for six months and jump in and expect that to come naturally -- not for me anyway."
With three races left in the regular season, Earnhardt is 21st in the standings and would need to return at Richmond and win to make the Chase for the Sprint Cup. The Hendrick No. 88 team currently holds the last spot in the team/owners championship playoff system, the same elimination-style points system that includes the same amount of bonus money paid to the driver champion.