JOLIET, Ill. — Tony Stewart knows he’s taking a gamble by leaving NASCAR’s elite Joe Gibbs Racing team to join one that usually runs in the middle of the pack.

But Stewart also can imagine what it might feel like to be in victory lane at the Daytona 500 both as a driver and a car owner, so it’s a risk he’s willing to take.

Having recently negotiated a release from his Gibbs contract at the end of this season, the two-time Cup series champion announced Thursday that he will join the team currently known as Haas-CNC as an owner-driver in 2009.

“There’s no guarantee that this is going to be successful,” Stewart said.

“But after sitting down and evaluating what the potential of this team is, I wouldn’t have made this decision if I didn’t think it would be successful and if I didn’t think it had the potential to be great.”

Stewart will be given a 50 percent ownership stake in the team, which will be renamed Stewart-Haas Racing. The two-car team currently fields the No. 66 car for Scott Riggs and the No. 70 car for Jason Leffler, and both cars are outside the top 35 in owners points going into today’s race at Chicagoland Speedway.

The move had been widely anticipated, but Stewart confirmed it to his current crew members and other Gibbs employees at the team’s race shop Wednesday.

“I wondered how it was going to feel,” Stewart said. “I wondered how everybody was going to react.”

But Stewart said after he spoke, several employees stood in line to congratulate him.

“We could never be mad or hold that against him,” said Stewart’s longtime crew chief, Greg Zipadelli. “His success, our success as a group, would not be possible without him.”

Stewart said the hardest part about his decision to leave was the fact that Zipadelli isn’t coming with him. Zipadelli will stay with Gibbs, and may end up being paired with 18-year-old racing phenomenon Joey Logano on the No. 20 team next year.

A plan to stay involved in NASCAR after he’s done driving is important to Stewart, who already has several financial interests in racing — including ownership of sprint car teams and grassroots race tracks.

Stewart and Haas-CNC general manager Joe Custer did not directly confirm the financial details of Stewart’s ownership stake in the team. But both Custer and Stewart strongly hinted that adding Stewart’s name and fame to the marquee was enough, and he wouldn’t be investing a large chunk of his own money.

The other 50 percent of the team is owned by Haas Automation, a California-based machine tool builder. The company’s founder, Gene Haas, began serving a two-year prison sentence for tax evasion in January.

Custer said Gene Haas was not involved in making the deal with Stewart. It was approved by another Haas executive, general manager Bob Murray.

Zipadelli said Stewart has matured in recent years, perhaps allowing him to better weather short-term challenges.

“He’s done a much better job at controlling his emotions on the bad days, when situations aren’t quite to his liking,” Zipadelli said. “I think if he doesn’t start off with the success he’s used to or wants, then when he gets it, it’s going to be much more fulfilling.”