The nine-time world champion in all categories was operated on in Ancona, eastern Italy, on Friday after breaking his right leg in a training crash near his home town of Urbino.
Doctors had estimated that the 38-year-old would need to remain in hospital for up to four days after surgery but he was discharged after just one night.
“I will do everything I can to get back as soon as possible,” Rossi said in a statement released by his Movistar Yahama team.
“I spent a good night, I slept, and this morning I felt good. The doctors visited me and they gave me the OK to go home, where I'll be able to rest even better.
“I will begin the rehabilitation as soon as possible and we'll see how my body reacts before making any decisions.”
The veteran racer is expected to be sidelined for two months, meaning he would miss the next two MotoGP races in San Marino and Spain but could possibly return in Japan on October 15th.
“It will depend a lot on him but I think that he will have to rest at least 40 days,” Dr. Raffaele Pascarella, who carried out the surgery, said Friday.
“However, he has already said he wants to return as soon as possible.”
Dr Pascarella said a nail inserted to stabilise the rider's leg would remain in place for 18 months.
This is the second time Rossi — who is lying fourth in this season's MotoGP standings after 12 of 18 races — has crashed this year. In May he was treated in hospital for chest and stomach injuries after a motocross training spill.
San Marino hosts the next race on September 10th with Rossi 26 points behind leader Andrea Dovizioso.