A lack of front-end feel had been prevalent almost throughout and Rossi has scored just two podiums to date on the Italian bike. At 33-years of age Rossi appears to have felt that he simply couldn't afford to wait any longer for success.
Audi's recent purchase of Ducati was touted as a possible route to success, but it is hard to see how the German giant - with no two-wheel experience - could instantly transform the project.
Over time, Audi will certainly be able to assist in terms of cutting edge materials, manufacturing techniques and aerodynamics - plus software and simulation/modelling - but solving rider 'feel' issues is far from a purely mathematical challenge.
For Yamaha, Rossi's return is largely a win-win situation.
Firstly it is an acknowledgement of their technical abilities and will doubtless bring huge marketing benefits, including the potential of a title sponsor, while if Rossi struggles it will be seen as down to the Italian rather than the bike.
The only risk is that Rossi's return will destabilise Lorenzo, who is currently enjoying incredible form, finishing no lower than second in the nine races he has finished this year. However, Lorenzo more than held his own as Rossi's 'number two' and will start next year as Yamaha's number one regardless of Rossi's return.
"We have run this 'super team' together in 2008, 2009 and 2010 and, during that time, we achieved the 'triple crown' titles with rider, manufacturer and team world championship victories for three consecutive years," Jarvis said of the previous Lorenzo-Rossi tandem, "The target for the future is obvious and we will do our utmost to achieve our goals.
"I have no doubt that with the experience, knowledge, skills and speed of these two great champion riders we will be able to challenge for many race wins and for the 2013 and 2014 world championship titles.
"The signing of Valentino completes our future planning for the Yamaha Factory Racing MotoGP Team. Now that this is done we will put our 100 per cent efforts into completing the job at hand and to supporting Ben Spies and Jorge Lorenzo in their search for race victories and for Jorge's 2012 world championship title challenge.”
Spies, Lorenzo's team-mate since 2010, announced his departure prior to the US GP.
After ten of 18 rounds, Lorenzo leads this year's world championship by 23 points over Repsol Honda's Dani Pedrosa, with Stoner 32-points from the top in third.
Rossi is eighth in the championship, two points behind team-mate and top Ducati rider Nicky Hayden, who has been re-signed for 2013. At the same stage last season Rossi was fifth in the championship with 108 points.