Joe Gibbs Racing will release Tony Stewart from his contract at the end of the season, ending an incredibly successful decade in which they won two championships and turned the organization into one of NASCAR’s best.

Stewart was expected to address JGR employees Wednesday, with an official announcement planned later in the day. In a release obtained by the Associated Press, team president J.D. Gibbs called the parting “bittersweet.”

Stewart’s departure opens the door for him to buy a NASCAR team. He’s had an offer since April to purchase the fledgling Haas-CNC two-car team.