Rossi's deeply-troubled marriage to Ducati - dubbed the Italian dream team - hit a new low at last Sunday's US Grand Prix when he crashed out from a lowly eighth place with three laps remaining.
Rossi has been unable to emulate the performances of Stoner who won 23 races and the 2007 world title on the Ducati which is known for its beastly table manners.
Rossi will use the current summer break to consider a last-minute plea from Ducati-Audi to stay while sources close to Rossi say he is "80 per cent committed" to a Yamaha return.
Rossi will be 34 at the beginning of the 2013 season and knows he cannot wait for Audi to deliver engineering upgrades in the hope of making the Ducati faster.
"It is a big risk to stay at Ducati because I can't wait to make my decision," said Rossi whose last race win was on a Yamaha in October 2010 in Malaysia.
"I will make my decision before the next race at Indianapolis.
"An important thing for me to consider is that in Ducati, I can be the number one and, in Yamaha, they have Lorenzo.
"I had some problems in the past with Lorenzo especially because I was angry with Yamaha.
"After all I did for Yamaha, they put in the team a very strong teammate so I was pissed off with Yamaha more than him. Now it is a different situation and I understand that Yamaha made the right choice for Yamaha."
Rossi left Yamaha at the end of 2010 after he was beaten by Spanish upstart Lorenzo in that year's world championship. Lorenzo has now consolidated his position as Yamaha's No.1 rider.
- AAP