Chicago - Defending champion Takuma Sato of Japan and three-time winner Helio Castroneves of Brazil are among six former winners in the 35 entries announced on Friday for the 102nd Indianapolis 500.

But the grandson of legendary Brazilian racer Emerson Fittipaldi, scheduled to be among four rookies seeking a spot in the 33-car field for the May 27 race, is likely out after suffering two suspected broken legs in a major crash in Europe.

IndyCar's signature event, 200 laps around the famed 2 1/2-mile (4km) Indianapolis Motor Speedway oval, will include four other past winners - New Zealand's Scott Dixon, the 2008 champion, Brazil's Tony Kanaan (2013) and Americans Alexander Rossi (2016) and Ryan Hunter-Reay (2014).

Practice starts on May 15. Qualifying is set for May 20-21 with bumping of slower cars from the grid expected for the first time since 2011 as more drivers than the minimum are attempting to qualify.

The 33-car field will be set May 20 with starting spots determined the following day, including the pole position.

Pietro Fittipaldi, whose grandfather was a two-time Formula One champion and two-time Indy 500 winner, was to drive an entry for Dale Coyne Racing.

But the 21-year-old Brazilian was hospitalised in Belgium after an accident in qualifying for the World Endurance Championship opener at Spa with what a WEC statement called "suspected fractures to both legs."

He likely will not join fellow Indy newcomers Brazil's Matheus Leist, Canada's Robert Wickens and American Kyle Kaiser at the oval later this month.

Danica Patrick will attempt to qualify for her eighth Indy 500 start in the last race of her career. She last competed in the 500 in 2011. Her third place showing in 2009 is the best result for a female driver at Indy and her breakthrough 2008 Indy Japan 300 victory is the only IndyCar triumph ever by a woman racer.

Andretti Autosport fields the most entries by one group with five, including Rossi and Hunter-Reay. Team Penske has four cars, including Castroneves, US reigning series champion Josef Newgarden, Australian Will Power and Frenchman Simon Pagenaud.

There are 21 entries from beyond US borders, including England's Max Chilton, Jack Harvey, Jay Howard, Pippa Mann and Stefan Wilson.