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PHOENIX (Reuters) - IndyCar driver Danica Patrick is widely expected to make a full-time move to NASCAR next year after announcing she will hold a news conference in Scottsdale, Arizona Thursday to discuss her plans for 2012.

Patrick has divided her time between IndyCar and NASCAR for the past two seasons but has come under increasing pressure to commit to just one of the circuits to achieve more consistent results.

The petite 29-year-old American has three top-10 finishes in seven starts this season on NASCAR's second-tier circuit, the Nationwide Series. Her best result was fourth in Las Vegas.

"Danica will be announcing her plans for 2012 tomorrow at a press conference," Patrick said on her website Wednesday.

A long-time darling of American motorsport, Patrick became the only woman to reach Victory Lane in an IndyCar race with a win at Motegi in Japan in 2008.

However, she has made no secret of her preference to race on oval circuits rather than on street courses in recent years as IndyCar has increasingly focused on street tracks.

"We didn't race road courses in IndyCar until 2005 and we only raced three at that point," Patrick told reporters before last month's Indy race in Edmonton. "I think we may have only raced three the next year.

"Then it was five and seven and 10. So we've definitely compounded the amount of road courses and we've unfortunately lost really great oval races."

This season, 10 of the 18 IndyCar races have been, or will be, held on street courses.

"I follow my heart and I think about where I'm going to have the most fun, where I'm going to have the best chance to win," Patrick said. "Those are the most important things."

(Writing by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue)