Davis had been expected to remain hospitalized overnight, but the Celtics said after the game that Davis had been released. Team spokesman Jeff Twiss said he did not know how long Davis would be sidelined.
The accident on the Massachusetts Turnpike happened around 2:30 p.m. No further details of the accident were immediately available, although snow fell throughout the day Sunday, making for hazardous driving conditions.
Davis, in his second season out of LSU, was taken to Brigham & Women's Hospital in Boston. Celtic president of basketball operations Danny Ainge went to the hospital to be with Davis.
Center Patrick O'Bryant replaced Davis on the active roster against the Knicks, and Boston tied a team record with its 18th consecutive victory.
Information from The Associated Press was used in this report.