(CNN) -- Formula One legend Michael Schumacher remains in a medically induced coma, according to his agent, while one of his former teammates is "praying" for his recovery.
The 45-year-old suffered a severe head injury while skiing on December 29 in the French Alps.
"Michael is still in the wake-up phase," said his manager Sabine Kehm in a statement on Friday. "The situation has not changed."
Germany's seven-time world champion was placed into a medically-induced coma to help reduce swelling on the brain.
Schumacher has had two operations to relieve pressure on his brain and to remove haematomas at Grenoble Hospital, France.
Kehm once again confirmed that "any medical information published which is not confirmed by the team of doctors treating Michael or his management has to be considered as not valid."
His friend and fellow racing driver, Felipe Massa, says he is optimistic Schumacher will recover after visiting him in hospital last month.
"I pray for him every day," Massa told CNN. "I believe things can be better and normal for him.
"I keep praying and hope everything will be fine."
Schumacher, who retired from F1 in 2012 following a record-breaking 19-year career, had been skiing off-piste when he fell and hit his head against a rock.
Last month, his family issued a statement where they said they still "strongly believe" in his recovery.
They also conceded that the "wake-up phase" can take "a long time."
Schumacher, who won five consecutive titles with Ferrari between 2000-04, also claimed two drivers' championships at Benetton in 1994 and 1995.
Unlike his friend, Massa has found success harder to come by and ended his eight-year spell at Ferrari to join Williams for the 2014 season.
The 32-year-old, who won eight grands prix with Ferrari, came agonizingly close to winning the drivers' title in 2008 only to be defeated by Lewis Hamilton in the final race.
Now the Brazilian hopes he can succeed with Williams following the unveiling of the British team's new car.
"It's my dream," said Massa of winning the sport's top prize.
"I always had this dream and I'll do everything I can to make it real.
"It's very nice and important to me. I was very close to achieving that.
"We keep wishing, fighting and I think we need to believe all the time that things can change from one year to the next.
"It's a new year and I hope we do well."