Porsche North America will scale back to a two-car factory effort for next weekend’s Petit Le Mans, which will see the GT Le Mans debut of rising star Earl Bamber in one of the team’s Porsche 911 RSR entries.

The German manufacturer confirmed to Sportscar365 Friday the change of plans, which was originally to see the continuation of a three-car program following the addition of the No. 910 Porsche in last weekend’s Lone Star Le Mans at Circuit of The Americas.

However, the unavailability of factory drivers for the ten-hour race at Road Atlanta has resulted in the withdrawal of the third car.

Richard Lietz, who continues his recovery from a broken arm, has been ruled out from making his return for the race, while Fred Makowiecki, who teamed with Patrick Pilet for a fifth place class finish at COTA, has Super GT commitments in Thailand.

Marco Holzer, meanwhile, had a pre-existing contract with Team Falken Tire to be its third driver for the TUDOR United SportsCar Championship season finale.

As a result, all focus will be on two cars, with 24-year-old Bamber to make his factory debut alongside Patrick Long and Michael Christensen in the No. 912 Porsche. The No. 911 entry will be driven by Pilet, Nick Tandy and Joerg Bergmeister.

Bamber, a two-time Porsche Carrera Cup Asia champion, currently leads the Porsche Supercup points standings with two rounds to go. The New Zealander tested with the factory squad at Road Atlanta in August, with encouraging results.

Bamber was originally listed to drive with NGT Motorsport for the race. No word has been given on his replacement for the No. 30 Porsche 911 GT America.

Porsche heads into next weekend’s season finale tied for the lead in the GTLM manufacturers’ championship with Dodge.