Formula 1 legend Michael Schumacher was placed in a medically induced coma this week after suffering a serious head injury this weekend while skiing, according to NPR.

Doctors treating the driver at the University Hospital Center of Grenoble in France said it was too soon to tell if Schumacher, 44, will be okay.

"We cannot predict the future for Michael Schumacher," chief anesthesiologist Jean-Francois Payen told reporters Monday, according to a report by the Associated Press. "He is in a critical state in terms of cerebral resuscitation. We are working hour by hour."

Schumacher, who retired for a second time in 2012, was skiing on Dec. 29 when he fell and hit his head on a rock, according CNN who spoke with the director of the Meribel resort where Schumacher was staying at the time.

He was wearing a helmet when he fell and hit his head, according to AP. Rescue workers reached him just minutes after the incident and airlifted him to Grenoble.

The former driver was already in a coma when he arrived at the hospital and immediately went into brain surgery.

At press time, he had one operation done but is still being kept in a coma, according to CNN.

Schumacher's most serious injury on the racetrack took place in 1999 when he suffered a broken leg during a crash. He also suffered a major neck and spine injury during a motorcycle accident in 2009, according to AP.

Before he retired, Schumacher was earning $60 to $80 million a year, according to Forbes. He won five world championships in a row from 2000 to 2004, and seven overall, according to AP.

Schumacher has a wife, Corinna, and two children, Gina-Maria and Mick.

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