After handing the Italian outfit almost 30m for the player in the summer, the striker's present side are keeping a tight grip on him.
"It's impossible to imagine such a scenario, not even in your worst nightmare," said Anzhi technical director German Chistiakov.
"At the time being suggested, Eto'o will be preparing for the season with Anzhi and he'll do so with all of his professionalism."
Zenit St Petersburg boss Luciano Spalletti has also ridiculed the rumour.
"This story is just journalistic invention," the Italian tactician noted. "It would be difficult for such a move to be done, I don't think it could be done.
"It would also be an admission of an error by Inter. Signing Eto'o would mean that the club don't have faith in their current players."