After two largely unsuccessful years with Ducati, Rossi will return to Yamaha next season.
But while his 2013 plans have dominated the headlines, the seven-time MotoGP champion said he is still fully focused on his 2012 programme with Ducati for now.
"Unfortunately we always start to speak about next year very early during the season," said Rossi.
"It doesn't change anything. It's not the last race or even the second to last race. It's the last third of the championship. There are six races to go.
"It's very, very long and we have a lot of different races where we can try to improve the bike.
"Our target is to try and do some good races from here to the end."
Ducati will introduce a new frame and swingarm at Misano this weekend.
Rossi is optimistic the upgrade is a step forward, but said he wanted to see how Ducati compared to its rivals in practice before making a judgement.
"We did a test here with some new stuff and it was two good days with quite good performance and good feeling," he said.
"Now we have to understand if we have improved, and how much compared to the other guys.
"It's a new chassis and a new swingarm, with some modifications in the size, the position and the stiffness.
"The comparison in the test was better than the bike that I used in Brno, so I will start tomorrow with the new stuff."