The accident occurred late on 17 November when the car in which Sergei Abramov was traveling collided with a truck. His bodyguard and his driver were also injured.
Abramov suffered a punctured kidney and broken ribs and underwent surgery at Moscow's Central Clinical Hospital.
Abramov's aide, Igor Tarasov, told reporters in Grozny that the prime minister was expected to remain in hospital several weeks.
"Our presumption, after consultation with the doctors, is that [Abramov] will remain under doctors' care until the end of the year and at the beginning of the new year he will return to his duties," Tarasov said.
Chechen President Alu Alkhanov ruled out the possibility of an assassination attempt against Abramov, saying the car crash was most likely an ordinary road accident. Alkhanov cut short a trip to Russian regions to return to the Chechen capital of Grozny.
Abramov was appointed to head Chechnya's Moscow backed administration a year and a half ago. In July 2004, he survived unhurt a bomb attack on his motorcade in Grozny.
The car crash occurred 10 days before Chechnya's 27 November parliamentary elections, the first since the current conflict in the restive republic pitting separatists against Russian forces began in 1999.