INDIANAPOLIS — The Indianapolis 500 is new again.

Danica Patrick is a proven winner with a legitimate shot at taking the checkered flag, all the top teams and drivers are back for the 92nd running of the Indy 500 and optimism is high for what should, for the first time in 13 years, truly be "The Greatest Spectacle in Racing."

Much of the optimism comes from the long-awaited unification of the two American open-wheel series in February.

Pointing to the strong mix of experienced drivers and young talent at Indy, longtime team owner Roger Penske said he's excited about the sport's possibilities, now that everyone's under the IRL IndyCar Series banner.

"You can feel and see the difference on pit road, with all the cars and people coming to watch practice and qualifying," Penske said.

"I've been telling everybody the black cloud has lifted," said Michael Andretti, a member of one of Indy's signature families and co-owner of Andretti Green Racing. "It's such a great feeling."

The drivers, too, are caught up in a rejuvenated Indy.

"Everybody's back, and that's just an incredible feeling," said Kanaan, considered by many the best driver never to have won here. "It's always a 33-car field, but this year it's just so competitive that anything could happen."

That includes a victory by Andretti Green Racing teammate Patrick, who last month became the first woman to win an IndyCar race.

A win on Indy's 2 1/2-mile oval, where the 26-year-old has finishes of fourth, eighth and eighth in her previous appearances, would be a huge boost for her and the series.

"I believe I can win the race," Patrick said. "I have a lot of confidence at this place."

As does Kanaan, who said he, like most everyone, expects the winner to come from the first three rows, inhabited by the top three teams in the 12-year-old IndyCar Series. Among them, they have won seven of the eight races in this decade.

Chip Ganassi Racing's pole-winner Scott Dixon and 2005 race winner Dan Wheldon will start from the front row, along with Ryan Briscoe, driving for 14-time Indy winner Team Penske.

The second of the 11 rows includes Penske's two-time winner Helio Castroneves, Andretti Green's Patrick and Kanaan, followed in the third row by teammate Marco Andretti, Vitor Meira from Panther Racing and Hideki Mutoh, the fourth AGR driver and the fastest of 11 rookies in the field.

Scattered through the rest of the lineup are nine drivers representing teams making the transition from the defunct Champ Car World Series, which was mostly a road and street racing circuit in recent years.

One such driver is 19-year-old Graham Rahal, son of 1986 Indy winner Bobby Rahal and one of the fresh, young faces IRL is hoping will bring the sport back to America's mainstream fans.

Rahal, who won his IndyCar debut last month on the street course in St. Petersburg, Fla., to become the youngest IRL winner ever, will start 13th in the third oval race of his career.

"We knew it was going to be tough coming over to the IndyCar equipment versus what we had in the past," said Rahal, who drives for eight-time Champ Car champion Newman/Haas/Lanigan Racing. "But we are going to keep on learning."

Will Power, a former Champ Car rookie of the year, acknowledges drivers' lack of experience on ovals is just one disadvantage.

"My team engineer says the IRL teams have a five-year, $50 million lead on us in the development of the Dallara cars, especially on the ovals. We're not going to be able to overcome that in a few races or even one season," the Australian driver said. "But we're making gains every time we go on the track."

Still, he's not ready to concede Sunday's race, where once again weather will be a factor.

A year ago, Dario Franchitti won the race shortened to 166 laps by rain.

This month, rain has washed away nearly half of the scheduled practice time and one of the four days of time trials. When drivers did get on track, temperatures were mostly below normal, and the cars were often buffeted by gusty winds.

Even Friday's one-hour "Carburetion Day" practice, the only time during race week the cars are on the track, was interrupted by rain.

But Sunday's forecast called for sunny skies and temperatures in the mid-to-upper 70s.

"Everything is going to change, and I think it's going to be a really tough race," Michael Andretti said. "I don't think anybody's going to be happy with their car. Everybody's going to be slipping and sliding, and they're going to be struggling.

"It's going to be the one who struggles the least and has the breaks go their way that's going to win it."