Spencer Stone "is awake, able to get out of bed and in good spirits," a statement by the UC Davis Medical Centre said, as video emerged of the stabbing in which Stone, a member of the US Air Force, was apparently coming to a woman’s rescue.
Surveillance video shows an altercation on a Sacramento street corner outside of a bar early Thursday, while a source close to the investigation told AFP that Stone was trying to defend a woman being harassed by a group of men when he was stabbed.
Police say Stone faces no criminal accusations in the fight.
In a press release Friday police said that they are continuing their search for his attackers and are looking for two Asian men and a woman who fled the scene.
Police have also told reporters that the assault was in no way related to a terrorist act or to the train attack that Stone and two of his friends helped foil while vacationing in France.
In August, Spencer and two friends who were vacationing in Europe overpowered a gunman on a Paris-bound Thalys high-speed train who was armed with a Kalashnikov assault rifle, an automatic pistol, nine cartridge clips and a box-cutter.
Stone suffered a severely cut thumb and a knife wound to his neck during the struggle with the gunman. He and others were given the Legion of Honour - France's highest recognition - by French President Francois Hollande at the Elysee palace.