HAMPTON, Ga. — As an heir to one of stock car racing’s royal families, Ty Dillon longs to have a Sprint Cup ride of his own.

For now, he’ll have to settle for being a NASCAR sub.

Dillon is filling in for injured Tony Stewart in Sunday’s race at Atlanta Motor Speedway, a chance to bolster his fledgling career behind the wheel of one of the sport’s most recognized machines.

‘‘It gives me a chance to showcase what I can do in these cars,’’ said Dillon, the grandson of longtime car owner Richard Childress and younger brother of Cup regular Austin Dillon. ‘‘Any time I can get more laps and more experience, it’s going to help.’’

Dillon celebrated his 24th birthday on Saturday by finishing fifth behind race winner Kyle Busch in the Xfinity Series race at Atlanta, a precursor to his ninth Cup race — and first in Stewart’s No. 14 Chevrolet.

Stewart is recovering from back surgery after wrecking on an all-terrain vehicle last month, keeping him on the sideline at the start of his farewell season. Brian Vickers filled in at the season-opening Daytona 500, and now it’s Dillon, who finished third in the Xfinity Series a year ago, stepping into the seat.

‘‘It does take away a little bit of the sting from not running more of a [Cup] schedule than I was hoping for,’’ he said. ‘‘Now that I have the opportunity, I can go out there and do what I want to do.’’