In a statement posted on their website, da Matta's RuSport team said the Brazilian driver is expected to move from the Theda Clark Medical Center in Neenah, Wisconsin, to a rehabilitation facility soon.

"Cristiano has made excellent progress in the past several days," said Champ Car medical director Chris Pinderski, who visited da Matta in Wisconsin on Wednesday. "Although he is still somewhat confused, he is now conversational in both English and Portuguese.

"Additionally, he has started to walk on his own for short periods of time with minimal assistance. We anticipate that Cristiano will be ready to make the transition to a rehabilitation setting next week."

Da Matta was injured on August 3 when he collided at high speed with a deer on the Road America track during a Champ Car test session.

He required emergency surgery for bleeding on the brain.