After suffering a concussion three months ago, NASCAR Cup Series champion Kurt Busch is retiring from racing on medical advice.

The 44-year-old made the announcement Saturday at the Las Vegas Motor Speedway, his home track and the place where he began his career. Associated Press reported for the first time. At a news conference, Bush said doctors told him “it’s best for me to ‘shut it down,'” according to the report.

Tyler Reddick will replace Busch in the No. 45 Toyota Camry at 23XI Racing for the 2023 season. Reddick had already planned to move from Richard Childress Racing (RCR) in 2024 to the 23XI team, which is co-owned by NBA legend Michael Jordan and NASCAR driver Denny Hamlin. He was able to switch teams a season early because RCR signed Kyle Busch, Kurt’s younger brother and two-time Cup Series champion, to a contract through 2023.

Kurt Busch drives the No. 41 Chevrolet SS in the NASCAR Cup Series

Busch was injured in a crash in July and has missed 13 races so far. He’s not the only Cup Series driver with an injury; Alex Bowman has missed two races with a concussion and plans to miss three more, according to the AP. These injuries led to design questions with NASCAR’s next generation carwhich was introduced this season.

Busch made his Cup Series debut in 2000 with Roush Racing in a Ford. Despite winning the 2004 championship with Roush, he was fired from the team and moved to Team Penske, then running Dodges, in 2006. His relationship with that team also ended badly after the 2011 season, and Busch spent the next few years driving Chevys for a number of teams, including Stewart-Haas Racing.

His last two moves were to Chip Ganassi Racing and then to 23XI for the 2022 season. The victory for the No. 45 Toyota at Kansas made Busch one of the few drivers to race and win with every NASCAR manufacturer in his career.

Kurt Bush

Kurt Bush

Busch won 34 races in 776 starts over 23 years and also won the Daytona 500 in 2017. He also competed in the Indianapolis 500 and the Rolex 24 at Daytona, as well as drag racing.

Bush’s passing marks the end of an era. He is the last active driver to compete with the late Dale Earnhardt, and the last since the first 10-car Cup Chase in 2004, when he won his only title. Other stars of that era, for example Jeff Gordon and Jimmy Johnsonalready retired.

Bush reportedly plans to remain an ambassador for longtime sponsor Monster Energy and has approached Fox Sports about a commentary job.