Truex doesn't drive for Joe Gibbs Racing. But his team's crew members work for JGR. And two are suspended for an altercation with Kyle Busch's crew chief.
Blaney will go from the 21 to the 12, while Menard moves to the Wood Brothers from Richard Childress Racing.
The crash between Kyle Busch and Martin Truex Jr. changed the entire complexion of Sunday's race.