Kurt Busch will be unavailable to race the FireKeepers Casino 400 at Michigan International Speedway Sunday because he's still recovering from a concussion.
Busch was injured after crashing in qualifying July 23 at Pocono Raceway.
He has missed the last two races with concussion-like symptoms.
Ty Gibbs will again replace Busch in the No. 45 Toyota for 23XI Racing.
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"I am continuing to make improvements every day," Busch wrote in a tweet Wednesday. "I know Ty will continue to do a great job representing 23XI and the No. 45 Monster Energy team this weekend in Michigan. I am working hard to get back to 100%, and it’s my hope to be back in the car at Richmond Raceway. Thanks to everyone for the continued support and I look forward to being back on track soon."
Busch appeared at the Charlotte FC match Wednesday. He said doctors told him to seek stimulation, and he was seen banging a drum at Bank of America Stadium.
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"We're looking forward to Kurt being back to 100% and on track," 23XI racing said in a statement.
Gibbs finished 17th at Pocono and Indianapolis. Michigan will be his first traditional oval in a NASCAR Cup Series race.
Busch has a waiver to hold his spot in NASCAR’s playoff field should he qualify. He does have a spot based on his May victory in Kansas.
The Associated Press contributed to this report.