Hamilton will replace 43-year-old Schumacher at Mercedes from next season after signing a three-year deal worth a reported £15million per season, ending his 14-year association with McLaren.
For Schumacher, six years after calling it a day first time around, the exit is looming again, although there are rumours he could yet replace Sergio Perez at Sauber after the Mexican's switch to McLaren, whilst an 'upstairs' role at Mercedes is also a possibility.
But Press Association Sport has learned that Schumacher's dithering on whether to re-sign with Mercedes for 2013 opened the door for the Brackley-based team to poach Hamilton.
Fearing Schumacher would say no and with only slim pickings available at the end of the campaign, Mercedes pushed for Hamilton, ultimately winning out in the battle of the contracts with McLaren.
Schumacher, however, was fully aware of the Hamilton negotiations, and did not interfere at any stage.
With just six races remaining of his 'second career' in F1, even he has admitted it has been far from a success.
Schumacher said: "I have had three nice years with the team which unfortunately did not go as well as we all would have wanted on the sporting side.
"I wish Lewis well and for the team to achieve the success we worked so hard for in the build-up.
"I would like to thank the team for their trust and all the guys for their unconditional commitment. I will now concentrate on the next races."
In 52 grands prix with Mercedes, Schumacher has managed one podium - a third place in Valencia this year - and one fastest qualifying lap in Monaco in May.
That, however, was not translated into pole due to him serving a five-place grid penalty for running into the back of Williams' Bruno Senna in the preceding race in Spain.
Schumacher repeated such an accident in Singapore on Sunday, only this time it was Toro Rosso's Jean-Eric Vergne he rear-ended, and with it incurring a 10-place penalty for next Sunday's race in Japan.
Such incidents only further tarnish his legacy, and will perhaps make him feel it is time to again call it a day.
Assessing his contribution, Mercedes team principal Ross Brawn said: "I would like to thank Michael for the important contribution he has made to the growth of our team over the past three seasons.
"His energy and commitment have never wavered, even when results have not matched our own expectations, and we are determined to finish the 2012 season together on a high.
"As always, it has been a pleasure to work with Michael."