Dale Earnhardt Jr., NASCAR’S most popular driver, announced Tuesday that he will retire at the end of the season. Earnhardt informed his team of his decision early Tuesday.

“After 18 seasons and more than 600 races behind the wheel, Dale Earnhardt Jr. will bring his NASCAR Cup Series driving career to a close at the conclusion of 2017,” the news release says.

The two-time Daytona 500 winner set an afternoon news conference with team owner Rick Hendrick to discuss his decision.

A third-generation NASCAR driver, he has been plagued by concussions the last several years, and he missed half of last season recovering from the latest head injury. It’s caused him to delay contract talks on an extension to drive the No. 88 Chevrolet, and now he appears ready to call it quits.

Earnhardt turns 43 in October, was married during the offseason and has stated he wants a family. He’s become a vocal advocate for research of sports-related brain injuries.

Earnhardt has won NASCAR’s most popular driver award a record 14 times. He has 26 career Cup victories, and that includes a pair of wins in the Daytona 500.

Earnhardt is a two-time champion in NASCAR’s second-tier series. But the son of the late seven-time champion has never won a Cup title.