After the news arrived that the team's protege and 2008 world champion is switching to Mercedes, some said McLaren simply didn't offer the Briton enough money or good enough contractual terms.
"We made a financial offer which is better than anyone in Formula One, other than himself, receives today," team boss Whitmarsh is quoted by Reuters.
"I know we made a very, very big financial offer."
Whatever went wrong for Whitmarsh, who insists he is happy to pair youngster Sergio Perez with Jenson Button, it has also gone wrong for Michael Schumacher.
"That was the requirement for a contract extension."
Schumacher's manager Sabine Kehm revealed that they let a summer option on his current Mercedes contract lapse.
Schumacher "would have been able to sign (for 2013) if he had wanted to earlier in the summer", she told the BBC.
Now, Sauber appears the seven time world champion's only real option to keep racing.
"It's true I was at Sauber," said Kehm, responding to reports she met recently with Peter Sauber and Monisha Kaltenborn.
"I have known them for years. But that doesn't mean anything more than I'm regularly there."
Willi Weber, Schumacher's former manager, doesn't know what went wrong.
"I saw him last at Monza, and he was full of energy and ambition, which convinced me completely that everything was in the bag with Mercedes," he told SID news agency.
Weber said he can imagine his former charge taking up a management or ambassadorial position with Mercedes now.
He would not advise Schumacher to take up Sauber's offer.
"No, and I have nothing against Sauber, but I do not think he wants to go from a global player to a private team," said Weber.