Larson was let go two weeks ago after using a racial slur while competing in a virtual race.
Kenseth joins Hall of Famers Dale Earnhardt, Jeff Gordon, Richard Petty and David Pearson as the only competitors to win a Cup Series championship, rookie of the year award and the Daytona 500.
The two-time Daytona 500 winner retired from Joe Gibbs Racing after the 2017 season, then came back for 15 races in 2018 for Roush Fenway Racing.
Kenseth was Cup rookie of the year in 2000 driving for Roush, where he captured his only championship (2003). He has 39 career wins.