Michael Schumacher's inability to provide Mercedes over the summer with a definitive answer on his future intentions prompted his bosses to swoop for Lewis Hamilton, AUTOSPORT has learned.
The seven-time champion had been weighing up whether or not he wished to continue with Mercedes for 2013, and team management had been eager to get an answer from him by the end of the summer break about his plans.
Had Schumacher been ready to sign a deal early on there was a high chance Mercedes would have agreed a contract extension.
However, Mercedes bosses could not get a firm answer from Schumacher about his plans - and became concerned that a late-call by Schumacher to not continue could have left the team scrabbling around to try and find a top-line replacement at a time when the driver market would be closed off.
Sources suggest that it was Schumacher's indecision that prompted the initial call to push on with the Hamilton talks.
AUTOSPORT understands that Schumacher was aware of the negotiations between Hamilton and Mercedes - and accepted that if a deal was agreed it would leave him with no race seat there in 2013.
Schumacher's future is now uncertain, with the seven-time champion not offering any hints on Friday about whether he was looking at other options on the grid or was now heading to retirement.
"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," he said in a Mercedes statement.
"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."
Schumacher's only realistic option to remain in F1 is a switch to Sauber, with his manager Sabine Kehm having been seen in talks with team management at last weekend's Singapore Grand Prix.