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The biggest race of the IZOD IndyCar Series season is here at last. But who can you count on to be fighting for the victory at this Sunday's Indianapolis 500? Here's a guide to the contenders and the pretenders.

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The Penske/Ganassi bloc - The Indianapolis 500 is basically a battle between these two mega-teams and everybody else. While there are several intriguing possibilities of an upset involving other drivers, expect this race to be decided amongst Team Penske and Target Chip Ganassi Racing . There may be a few that stick their noses into these two rival's high-speed chess match, but when the race hits the final stages, Penske and Ganassi's squads will be up front to determine the outcome - again.

But which one of these drivers is a good bet to win? The answer is obvious in defending champion Helio Castroneves . A fourth Indy 500 victory would put him in the company of Brickyard gods A.J. Foyt, Al Unser Sr. and Rick Mears as four-time winners of the world's greatest race and you can bet that's enough motivation for him. Armed with plenty of momentum after crushing the "Fast Nine" pole shootout last weekend, he could run away with this.

As Graham Rahal said Thursday, Castroneves "is on his own planet."

Alex Tagliani, FAZZT Race Team - If Penske/Ganassi are the proverbial Death Star of the Indianapolis 500, Tagliani may be a Luke Skywalker of sorts. While his team is new to the Speedway, a fantastic week of practice and a strong run in qualifying (he's starting fifth) have moved him from intriguing underdog to legitimate favorite. A win by Tagliani (or his equally fast teammate for Indy, fellow Champ Car alum Bruno Junqueira) puts this squad in elite status. As he said Thursday, the 500 is a race that can change your life.

Contenders

There are a lot of drivers in this field that have the ability to win at Indy, but are going to need a break or two in order to take down the usual front-runners:

Graham Rahal, Rahal Letterman Racing - What kind of story would it be if the lead-footed Buckeye was able to score a victory Sunday?. Obviously, there's the whole "like father, like son" thing with his dad/team owner Bobby being the '86 Indy winner. Then there's all the trouble Graham had in landing a full-time sponsor to help him continue his career. A victory at Indy may be enough to finally get prospective backers in his corner - perhaps his Brickyard sponsor, the Kim Kardashian-promoted Quick Trim, would get hooked and go full-time with him. No matter the scenario, the IZOD IndyCar Series needs him as a regular on the grid. Winning here would help him get much closer to that goal.

Ed Carpenter, Panther/Vision Racing - The Indy native has been through a lot over the offseason, seeing his stepfather Tony George's team suspend operations over a lack of funding. But a victory here for Carpenter may be the ticket to bringing Vision back to life. He's always been relatively good here and if he can get a solid ride under him - especially in the draft - he can make some serious noise.

Dan Wheldon, Panther Racing - The 2005 Indianapolis winner is always a force on Race Day and his team, while a bit removed from the heights they reached with Sam Hornish Jr. in the early 2000s, knows how to get around the famed 2.5-mile speedway. Wheldon was second last year in the No. 4 machine, and in 2008, Vitor Meira (now with A.J. Foyt Racing) came home as a runner-up as well. Whether he's aggressive or methodical in his approach to the front, don't be surprised to see Wheldon running around in the top five with about 20 or 30 laps to go.

Townsend Bell, Chip Ganassi Racing/Sam Schmidt Motorsports - With two solid team owners behind him and a stout machine to drive, Bell certainly has the tools to make some magic. But after not being able to land a ride after finishing fourth last year in a one-off for KV Racing Technology, he's also back with a 'go-for-broke' philosophy that may the biggest weapon he has in his favor.

"I don't think, 'Gee, if I win the Indy 500, I'm going to be racing full-time with a great team,'" Bell said. "I'm just thinking, 'Win the Indy 500.' If I can do that - if nothing else happens in my career - I'll be thoroughly pleased."

Bruno Junqueira, FAZZT Race Team - The Brazilian instantly became somebody to watch after he threw down a qualifying average of 225.6 mph in a second FAZZT machine. He has experience at IMS, and considering the roll that his team is on right now he could work his way into being a late threat. He'll be starting 25th, which could make for an entertaining run to the front.

Tony Kanaan, Andretti Autosport - With a harrowing Bump Day saga behind him, TK will be starting 33rd on the grid after flipping to his repaired primary machine - the car he crashed on Pole Day. The 2004 IZOD IndyCar Series champion proved himself again as one of the best in the game with his efforts to make the show last Sunday, and he simply can never be counted out. But will the Brickyard finally show him some love?

Marco Andretti, Andretti Autosport - It'd be a mighty big deal if the son of Michael and grandson of Mario sips the milk in Victory Lane at Indy. However, his entire team has been off all month and he'll be starting in mid-pack (16th). Patience could be critical for Andretti 3.0, but it may not be enough to get more than a top-10 if he doesn't have a solid race pace.

Ryan Hunter-Reay, Andretti Autosport - Ditto for RHR, who's facing the possibility of going off the grid after the next race at Texas Motor Speedway in June due to sponsorship woes. With the clock ticking on his season, a strong run at Indianapolis may be enough to have IZOD continue to fund him or get another sponsor to take their place. However, he's had some struggles in finding speed this month as well.

Justin Wilson, Dreyer and Reinbold Racing - This team is doing a lot better in 2010 and their four-car team has solid driver talent. But for a 500-mile race, and all the twists and turns that take place in it, one just has the hunch that the steady Englishman will be able to stay steady, carry their banner on Sunday, and take home at least a top-ten finish - if not a top-five.

Raphael Matos, de Ferran Dragon Racing - The reigning IndyCar rookie of the year has flown under the radar but qualified a solid 12th on the grid. With former 500 winner Gil de Ferran now part of the ownership group, Matos has a fantastic resource to tap into for knowledge and advice on how to handle the historic venue. While a win may be out of reach, a top-10 is very doable for the young Brazilian.

Outside looking in

It'll be tough sledding to get into the top 10 for this bunch.

Hideki Mutoh, Newman/Haas - Qualified a solid ninth last weekend, but let's see if he can stay there.

Vitor Meira, A.J. Foyt Racing - His 30th-place qualifying run was a bit strange considering his team has usually been decent at IMS. How much is that going to hurt him?

Mario Moraes, KV Racing Technology - He has the speed, but does he have the patience? People remember his embarrassing first-lap crash last year with Marco Andretti.

Tomas Scheckter, Dreyer and Reinbold Racing - It's tough to put him in this section, but with the number of dark horses that have emerged, he may have a tough haul ahead of him.

Mike Conway, Dreyer and Reinbold Racing - He and Scheckter took each other out in an iRacing simulation race for the media on Thursday morning. That's probably not a good omen.

E.J. Viso, KV Racing Technology - Like his teammate Moraes, he needs to stay steady.

John Andretti, Richard Petty/Andretti Autosport - He'll likely make a pretty good jump from 28th starting position, but a top-10 may just be out of reach.

Danica Patrick, Andretti Autosport - Let's see if the gremlins on her car have disappeared. If they have, she'll work her way up. If not, she's in trouble.

Davey Hamilton, de Ferran Dragon Racing - The oldest driver in the field will be competitive, but getting into the lead pack may be too tall an order.

Thanks for coming

And here come the long shots ...

The three other ladies ( Ana Beatriz, Dreyer and Reinbold Racing ; Sarah Fisher, Sarah Fisher Racing ; Simona de Silvestro, HVM Racing ) - Beatriz and de Silvestro are rookies trying to get a handle on the legendary Speedway, while Fisher is a seasoned veteran. But it doesn't seem like they'll be anything but mid-packers at best.

Bertrand Baguette and Mario Romancini, Conquest Racing - Baguette managed to qualify in the top 24 on Pole Day, and Romancini showed that he's got guts; after withdrawing his qualifying time on Bump Day, he then ran a 224.6 average to cement his place in the show. But both Conquest rookies are likely to be in the bottom half of the field on Sunday.

Alex Lloyd, Dale Coyne Racing - He doesn't exactly have the fastest ride this month. But with a special white-and-gold Boy Scouts paint job, it's one of the better-looking pieces at least.

Takuma Sato, KV Racing Technology - With an extensive Formula One career, Sato's used to driving in big races. But he's about to find out that there's nothing bigger than Indianapolis.

Sebastian Saavedra, Bryan Herta Autosport - Five days afterward, his story of how he made the field remains bizarre. To dust off an old chestnut, it'll be a hell of a story to tell his grandkids one day. Seeing the checkered flag is likely his main goal.