INDIANAPOLIS (AP) — Helio Castroneves monitored the first four IndyCar races of the season from afar.

He learned to cope with the emotions of competing outside the series, being away from longtime friends and surrounded by his biggest fans. The itch to be out there, competing never waned, though.

On Friday, the beloved Brazilian will get the best belated birthday gift he could: Returning to the track as he prepares to make his season debut Saturday in the IndyCar Grand Prix.

"It's really hard when you drove for 20 years and all of a sudden you're doing something else," Castroneves said Thursday as he celebrated his 43rd birthday. "It doesn't connect. But I'm super happy have the opportunity I do have."

Sure, he knew this day would come.

But the wait has been the hardest part for one of the world's steadiest open-wheel drivers.

After making 344 starts, winning 30 races, collecting 141 top-five and 226 top-10 finishes and placing fifth or higher in IndyCar points 13 times in 16 full-time seasons, Castroneves' career turned in a new direction.

He switched to Roger Penske's new sports car program after last season and now anchors one of the team's Acura entries along with defending series champion Ricky Taylor and is happily running full-time on the IMSA circuit.

"It's great to be back, awesome," Castroneves said during last week's testing. "It's like you're playing with your old toy that (you) miss so bad."

Castroneves' comeback couldn't begin at a better venue, either.

Only three drivers — A.J. Foyt, Al Unser and Rick Mears — have more Indianapolis 500 wins than Castroneves, who also has three runner-up finishes and three additional top-fives in 17 starts on the 2.5-mile oval.

For now, though, Castroneves must remain focused on tinkering with this year's new aero kit on the track's 2.439-mile, 14-turn road course. Practice begins Friday morning with qualifying set for later in the day. There will be another practice round Saturday morning prior to the race.

Weather conditions could create another wrinkle. Saturday's forecast calls for a high temperature of 93 degrees with a 20 percent chance of rain.

"It should be a bit different than the last two years. It should be a bit warmer, as well, so that should change how the race is going to go," defending winner and Penske teammate Simon Pagenaud said. "I think the drafting is pretty good here. It's been strong on the straightaway, so you can certainly get sucked up really well, you can follow closer and not get as affected as before. So there's more opportunities (to pass) for sure."

Fortunately for Castroneves, he's in the best situation of any part-time driver.

He's been with Penske's team 19 seasons, has a crew he's worked with previously, three teammates he worked with last year and just happens to be driving for a team that has won three of the last four series championships and each of the four other grand prixs at Indy.

The question, of course, is how long will it take Castroneves to get up to speed?

Penske's ballyhooed return to IMSA started slowly. Then last weekend, Castroneves and Taylor drove to their first victory in a race at Mid-Ohio.

Castroneves also won the pole — nipping fellow Penske driver Dane Cameron for a 1-2 Penske start to the race — and he and Taylor combined to lead a race-high 87 laps. The other 38 laps were led by Penske teammates Cameron and Juan Pablo Montoya, who finished second.

It was Team Penske's first IMSA win in nearly 10 years, and Castroneves' first win on the circuit since taking the LMP2 class win in the Motul Petit Le Mans at Road Atlanta on Oct. 4, 2008.

That gives Castroneves momentum heading into the weekend — and renewed hope of becoming the first top-series level driver to win on both of Indianapolis Motor Speedway's courses.

"I do think about that and I have been thinking about that since this race started," Castroneves said. "I'm ready to go here."

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Associated Press Auto Racing Writer Jenna Fryer contributed to this report.

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