Franck Montagny will be Andretti Green's primary driver for the rest of the American Le Mans Series season after the team decided to stand down regulars Christian Fittipaldi and Bryan Herta.
Former Super Aguri Formula One driver Montagny, who was part of Peugeot's Le Mans 24 Hours team, will be joined by Marco Andretti for the forthcoming Lime Rock round, but the identity of his co-driver for the balance of the season has not yet been announced.
While Fittipaldi only joined AGR this year, Herta has been part of the squad since 2003, initially racing for their IRL IndyCar Series operation before switching to the ALMS when he lost his IndyCar drive to Danica Patrick in 2007.
Team owner Michael Andretti paid tribute to the ousted duo, but said the drastic change had been necessary.
"Making a change in the middle of the season isn't something you enjoy, and I think it's even tougher in this case because we're talking about Bryan and Christian," said Andretti.
"Bryan has done everything we've ever asked him to do since he joined Andretti Green in 2003, including helping us win the 12 Hours of Sebring in our first American Le Mans Series start last year.
"Christian joined us this year and wanted to win as badly as we did. We will always appreciate the effort that both Bryan and Christian gave to the team."
Although AGR won the LMP2 class on their series debut at Sebring last year, they have been unable to repeat that success since.
Andretti believes Montagny, who has been a Le Mans regular for many years, will be an instant success in the ALMS.
"We're looking forward to seeing what Franck can do in the XM Acura," said Andretti "He's got a lot of experience in different types of cars, including prototypes, and that should help him adjust pretty quickly to what we're doing here."
Montagny finished third both at Le Mans, and in the final Champ Car race at Long Beach this year. He had been set to contest the full season for Forsythe Racing before the merger with the IRL and Forsythe's subsequent exit.
The Frenchman feels his AGR ALMS call-up is a great opportunity.
"I know how competitive the American Le Mans Series is and know how challenging this will be, but I believe I am ready for it," said Montagny. "I am eager to get started."
Marco Andretti, who was very quick in the AGR Acura on a guest appearance at Sebring, will fly between his IndyCar duties at Nashville and the ALMS race at Lime Rock on the 12 July weekend.