Joe Gibbs Racing President J.D. Gibbs is undergoing treatment for "symptoms impacting areas of brain function," which likely stem from a head injury suffered earlier in life.
JGR did not reveal a specific diagnosis in a statement Wednesday, but said Gibbs is undergoing treatment to manage symptoms that began with "speech and processing issues."
The 46-year-old is the oldest son of team owner Joe Gibbs, the NFL Hall of Fame winning coach of three Super Bowls with Washington.
"All members of the NASCAR and France family extend our thoughts and prayers to J.D. Gibbs and his loved ones," NASCAR Chairman and CEO Brian France said in a statement. "We've all watched J.D. grow up within our community, and he always has represented himself, his family, the entire Joe Gibbs Racing organization and NASCAR with the utmost professionalism, enthusiasm and energy. We wish him the best during this time and eagerly anticipate his recovery."
JGR said doctors believe the symptoms are related to previous head injuries, but no specific injury has been identified.
J.D. Gibbs previously played football and had a brief career as a race car driver. He also snowboards, mountain bikes and participates in other extreme sports.
JGR expects J.D. Gibbs' presence at the race track to be limited while he undergoes treatment at an undisclosed location. But he's expected to continue many of his day-to-day responsibilities at the team shop, as well as his ministry endeavors.
JGR fields four Sprint Cup Series cars for Kyle Busch, Denny Hamlin, Matt Kenseth and Carl Edwards, who was added to the organization this year. The team also has three teams in NASCAR's Xfinity Series, a driver development program and competes in SuperCross.
J.D. Gibbs was named team president in 1997 and oversaw the expansion of JGR from a one-car team into one of NASCAR's powerhouses.
He's held several positions for the company, which currently employees more than 500 people. His range dates back to the 1993 Daytona 500 — the first victory for JGR — in which J.D. Gibbs was a tire changer during the race.
J.D. Gibbs ran the operation from 2004 through 2008 when his father returned to the NFL for a second stint coaching Washington. During that time, the youngest of J.D. Gibbs' four sons was diagnosed with leukemia.
He and wife, Melissa, currently host Taylor's Finish Line Festival at Charlotte Motor Speedway's drag strip to benefit the Make-A-Wish Foundation and Levine Children's Hospital in honor of Taylor, who is in remission after three years of chemotherapy treatments.