SONOMA (AP) — After Tony Stewart wrecked his NASCAR season by breaking his leg in a sprint car crash, Helio Castroneves admits he wondered whether it was such a good idea to drive a Brazilian stock car on an unfamiliar street course in the middle of the IndyCar season.

Castroneves is a race car driver, so he did it anyway.

And he barely emerged intact from a wreck of his own.

“It wasn’t a fun call from Roger (Penske),” Castroneves said, grinning.

Castroneves realizes he nearly ruined his chance to win his first IndyCar championship in his Team Penske Chevrolet with his misadventure two weeks ago in Ribeirao Preto. His brakes failed at more than 120 mph before a tight turn on a brand-new course, and he slammed his stock car into a wall.

After three stitches on a bone-deep cut in his shin and a few days of rest for his sprained neck, he’s ready to resume the IndyCar chase. He leads Scott Dixon by 31 points in the standings with five races left in the season.

“My biggest concern was a little pain in the neck, because it was such a violent hit,” Castroneves said Friday after practice at Sonoma Raceway. “But they took X-ray, CAT scan, MRI — they did everything that’s possible. Thank God it was clear. By Wednesday, I was 100 percent. I’m still a little bruised in my ribs, but the position that we sit in the (IndyCar) car, the belt actually avoids the ribs. Honestly, I don’t feel a thing, so I’m very happy.”

So why would Castroneves even take the chance of competing in a meaningless stock car race when he’s so close to the IndyCar title he’s been chasing for more than a decade? And why would he do it just four days after Stewart demonstrated the dangers of dabbling in minor races with his crash in Iowa?

Castroneves said it’s because he agreed to the deal back in April with the prominent support of sponsor Shell Pennzoil. The race organizers even moved the date to avoid a conflict with the IndyCar schedule.

“I made commitments, and sometimes when you make commitments, it’s hard to just say, like, ‘Listen ...’” Castroneves said. “They prepared the car, and they were sending pictures to see how the car was being done. I even had second thoughts after Tony Stewart had a little issue, broke his leg. I’m like, ‘Oh, man, this is not going in the right direction here.’ But sometimes, it happens for a reason.”

With its elevation changes and nasty corners, the Sonoma road course requires drivers to be in tip-top shape. The race often plays a pivotal role in the IndyCar championship chase, with points leaders frequently getting pulled back to the pack in the standings by bad Sonoma performances in recent years.

Castroneves, who won at Sonoma in 2008, believes he can buck the trend even while acknowledging the difficulties of the track nestled between wine country and the San Francisco Bay. He had the second-fastest practice time Friday.

“I’m not sure if it’s wind or the sand that blows into the track, but it’s very tough because the track becomes a little slippery,” Castroneves said. “It depends on where the wind is going. This morning, it was one way, and now it’s another way. It can get very confusing. That’s why it’s so difficult — not only because of that, but because of blind corners as well. Sometimes you can’t see what’s right after the corner, so it’s a big challenge. It’s a tough business.”

He has been one of the circuit’s most consistently successful drivers for more than a decade, finishing in the top six in 10 of the past 11 years. He finished second in 2002 and 2008, but has never won the overall title.

Defending Sonoma champion Ryan Briscoe also is playing hurt after breaking his right wrist in Toronto last month. Briscoe is eager for his first race since undergoing surgery, but acknowledges he’s at only 90 percent effectiveness while wearing a brace on his wrist.

“I’ve been training, so I’ve got a pretty good grip on the wheel,” Briscoe said. “I guess we won’t know until the end of the race whether I start fatiguing or not. The biggest challenge has been getting used to wearing the brace in the car, because initially it was getting in the way on the hairpins and stuff. We’ve tried to figure out a method where it doesn’t catch on the belts or anything.”