Herta confirmed at Andretti Green

Franchitti recently made his return to racing after missing three IRL races following a motorbike accident. However, orthopaedic surgeon Dr Terry Trammell advised the Scot that he should skip the remainder of the season for surgery. Andretti Green Racing thus turned to Bryan Herta, who filled in for Franchitti at Texas Motor Speedway recently.

"This is an unexpected surprise," said Herta, who finished fourth in his Texas outing. "It was a shock to find out about Dario, but I'm glad I have a relationship with Andretti Green Racing and that I got the call."

Herta's late call-up gives him little time to prepare for this weekend's night race at the tough, three-quarters of a mile Richmond oval, but the American is ready for the challenge.

"I like these night races; it gives me a chance to sleep in," he joked. "I have never raced at Richmond, and it is only a two-day show, so there is very limited track time. The team has tested there and Tony [Kanaan] found some things, so I think we will be all right.

"I would be more worried if working with the team was completely new, but after working with them at Texas I know if we can unload a good car off the trailer, we will be fine."

Team boss Michael Andretti said: "Bryan did a great job for us in testing and during the race at Texas. He fits in well with the team and with Tony and Dan [Wheldon]. One of the things that makes our team successful is the relationship and trust each of the drivers have with one another.

"With one race and a couple of tests under his belt with AGR, Bryan has shown he works well in that environment."