Overall, 39 cars were on the entry list released Friday by the Indianapolis Motor Speedway, but most of the teams will have at least one backup car for each of their drivers.
Practice for the May 25 race will begin with the annual rookie orientation program May 4.
The 19-year-old Rahal, son of car owner and former Indy winner Bobby Rahal , won his IndyCar Series debut last week in St. Petersburg, Fla., becoming the youngest winner of a major open-wheel race in North America.
Former winners entered this year are Helio Castroneves (2001 and 2002), Buddy Rice (2004) and Dan Wheldon (2005).
For the second consecutive year, three women are entered: veterans Danica Patrick , Milka Duno and Sarah Fisher , who will drive for the first time as owner of her own team.
BIFFLE ADAPTING: Some drivers have become chronic complainers about NASCAR's new generation car, a bigger, bulkier vehicle dubbed the Car of Tomorrow when it was introduced.
But Greg Biffle , whose Roush Fenway Racing team --- led by teammate Carl Edwards with three victories --- has come closest to mastering the new car this season, pointed out that NASCAR isn't planning to change the car anytime soon.
"It's what NASCAR wanted... NASCAR built this car, and it's our job to race it, race it the best we can, get it to handle the best we can and do what we can with it,'' Biffle said. "That's out job, so that's what we're going to focus on and we're going to work on, and we'll just let nature take its course."