"Politically they have always tried to employ the best possible drivers who were available. Not who they could afford but who were available," he told the Guardian.
"There were other options and some of those were probably ones I would have gone for," said Watson, who said Nico Hulkenberg and Kimi Raikkonen would have been better choices in his opinion.
"Unfortunately they've ended up with Perez and the fact he's associated with Carlos Slim will have some value to McLaren," he continued.
"McLaren have always sought the best talent and clearly that is not the case right now," the 66-year-old Briton added.