ESPN IndyCar

INDIANAPOLIS -- Most years, there are several drivers who stand out as favorites to win the Indianapolis 500.

Not this year.

One racer has been the absolute class of the IndyCar Series in 2008 on oval tracks, though he only has one win to show for it. Scott Dixon dominated at Homestead (where he won the season opener), Motegi and Kansas, and he's been the pacesetter at the Indianapolis Motor Speedway in practice and qualifying for Sunday's 92nd running of the Indianapolis 500 (ABC, noon ET).

The New Zealander who drives the No. 9 Dallara-Honda for Target Chip Ganassi Racing won the IndyCar Series championship in 2003, his first year in the series. Preparing now for his sixth start at the Brickyard, Dixon has established himself as the man to beat when honorary starter -- and "Dancing With The Stars" champion -- Kristi Yamaguchi waves the green flag just after 1 p.m. ET.

That's not to say Dixon is going to have an easy run of the Memorial Day Classic. A couple of drivers stand out as obvious challengers, including former Indy 500 champions Dan Wheldon and Helio Castroneves.

But beyond that, the 500 field is a bit thinner than it was a year or two ago despite the presence of several teams and drivers from the defunct Champ Car World Series. The main deficiency: the past two Indianapolis 500 winners and IndyCar Series champions (Sam Hornish Jr. and Dario Franchitti) no longer are racing open-wheelers.

In fact, if you start assessing each of the 33 drivers' chances Sunday, the 500 form guide starts to resemble a pyramid: Dixon on top, with two drivers likely to be his closest competitors, three drivers probably half a step off that trio's ultimate pace, four drivers who could win through radical strategy, and so on down the line.

With that pyramid image in mind, here is how ESPN.com ranks the contenders competing:

Level 1
Scott Dixon -- Dixon has led 313 of 600 oval laps this season, more than three times as many as his nearest challenger. He was unlucky not to win at Kansas and Motegi, and surprisingly, his only bad outing came on the street course in St. Petersburg, Fla. Dixon and the No. 9 team seem to have a more intense focus this year, and one gets the sense that Indy is their biggest prize.

Level 2
Tony Kanaan, Dan Wheldon -- Like Dixon, Kanaan is a former IndyCar Series champion who is arguably due to win the 500. Andretti Green Racing couldn't match the qualifying pace of Ganassi and Team Penske, but don't kid yourself into believing TK won't be a force in the race. Wheldon has cooled his over-the-top "I love Indy" rhetoric this year, but make no mistake, it is still the one race he most wants to win and the Ganassi team has made an Indy victory a 2008 priority.

Level 3
Helio Castroneves, Marco Andretti, Danica Patrick -- Castroneves is a two-time Indy winner, but some question whether the distractions from his "Dancing With The Stars" victory tour have been a problem. The charismatic Brazilian always shines when the pressure is on. Andretti and Patrick have the benefit of running Kanaan's AGR setups, and the only question is whether they can put together a strong and consistent enough effort in the course of 500 miles to stay with the IndyCar Series' acknowledged big four.

Level 4
Tomas Scheckter, Ryan Briscoe, Vitor Meira, Ed Carpenter -- Now we're down to the level where a win by anyone from this group would have to be considered somewhat of a surprise. Scheckter's speed is beyond question, but he's likely to be a little rusty running a part-time schedule, and race-long focus has never been his strong suit. Briscoe used his top-notch Penske equipment to land a front-row starting spot, but the Australian still makes too many mistakes to be thought of as a favorite. Meira is the sentimental choice, but his breakthrough first win probably isn't going to come at Indianapolis. Carpenter continues to show the emerging promise of Tony George's Vision Racing team.

Level 5
Justin Wilson, Graham Rahal, Oriol Servia, Will Power, Buddy Rice -- Wilson, Rahal, Servia and Power are the top newcomers from the Champ Car series, but the odds of any of them winning the Indianapolis 500 on their first attempt are extremely long. Rice is a former Indy winner, and his hopes depend on whether Dreyer & Reinbold Racing can execute a pit-stop strategy that puts him out front.

Level 6
Ryan Hunter-Reay, Darren Manning, A.J. Foyt IV, Bruno Junqueira, Davey Hamilton, Hideki Mutoh -- Here are half a dozen quality racing drivers and human beings, but don't expect to see their image on the Borg Warner Trophy -- at least not this year. Rahal Letterman Racing is high on Hunter-Reay, and he could really shine in the future with the benefit of a well-matched teammate. Manning (in A.J. Foyt's car) and Foyt IV and Hamilton (in Tony George's cars) will be fan favorites but won't win. Junqueira deserves a good result after Foyt IV put him in the hospital in his most recent Indy start; if the Brazilian were in Mutoh's No. 27 AGR car rather than in a Dale Coyne Racing entry, the former Indy pole winner might rank in the second or third tier.

Level 7
Buddy Lazier, Townsend Bell, Alex Lloyd, Sarah Fisher, Jeff Simmons, Enrique Bernoldi, John Andretti -- Some great stories in this group, but not an Indy 500 winner. Former champion Lazier showed his mettle with a gutsy Bump Day qualifying run; Fisher is the people's choice; Lloyd is coming back from a practice crash; and Bell is buds with Justin Timberlake and drives a slick-looking matte green car.

Level 8
Marty Roth, Milka Duno, Mario Moraes, Jaime Camara, EJ Viso, Mario Dominguez, Kristi Yamaguchi, Tony George -- I feel kind of bad about lumping Moraes, Camara and Viso in with Milka and Marty. But they have a similar chance of winning Sunday.

As for the Level 8 field fillers: Dominguez is the first alternate and could get in the show if someone crashes beyond repair on Carb Day; Yamaguchi is just waving the green flag yet still is as likely to win as Milka and Marty are.

And though Tony George isn't driving in the 500 and it would even be a shock if one of his cars won, the Indianapolis Motor Speedway CEO could be a winner anyway if attendance and television ratings are up over recent years.

That's one victory you should be able to count on.

John Oreovicz covers open-wheel racing for National Speed Sport News and ESPN.com.