The 38-year-old completed 20 laps around the Misano circuit on Tuesday after Monday's first training session was cut short by rain.
"I managed to complete 20 laps and find the answers which I had been looking for," the nine-time world champion said.
"Obviously at the end of the test I had a bit of pain, but this morning (Wednesday) I went to Dr. (Raffaele) Pascarella for a medical check-up, and the result was positive.
He added: "See you in Aragon."
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Rossi underwent surgery on September 1, a day after a crash in training, discharging himself from hospital the following day.
His Yahama team said the veteran racer would undergo more tests in Spain before competing.
If Rossi cannot compete his place should be taken by Dutch Superbike rider Michael van der Mark.
Rossi missed the San Marino Grand Prix but remains fourth in the standings, 42 points behind world champion Marc Marquez of Spain and Italy's Andrea Dovizioso with five rounds to go.