Rossi completed 46 laps on a Yamaha YZF-R1 Superbike, the same bike he rode on his return to racing a week ago at the Misano circuit in Italy. His best time on Monday was 1 minute, 59.135 seconds.
"Today was good, I felt better than in Misano but I still feel quite tired after a few laps and a race will be a much bigger question," Rossi said.
The 31-year old Rossi is contemplating a return to competitive action at the weekend at the German Grand Prix, but could delay until the Czech Grand Prix in Brno on August 15.
"We haven't made the final decision yet," he said "I need to have some more X-rays on Wednesday and then my doctors and I will consider whether I can ride at Sachsenring."
If he was to ride in Germany, he would require clearance from the MotoGP medical director. If he does not pass the required tests, Japanese rider Wataru Yoshikawa will again replace Rossi, as he did at the Catalunya Grand Prix earlier in the month.
The seven-time champion underwent surgery for two-and-a-half hours following a crash in qualifying for the Italian Grand Prix on June 5. He was expected to be out of action for three to four months.