Out of troubled engine supplier Renault's four F1 partners, including Toro Rosso, the senior Red Bull team managed the least mileage of all at the recent Jerez test.
Minardi, however, observed that - officially - the Red Bull-owned teams are sending out messages of "tranquillity and calm" about what many others believe is a crisis.
"According to circulating information, the situation seems more difficult than that and not easy to solve," the 66-year-old wrote in a posting in Italian on his website.
"It seems that Red Bull are exploring a possible change of engine for 2015," added Minardi.
He said he has also heard that Renault, struggling to solve the obvious problems with its turbo V6 'power unit', has gone beyond the walls of its Viry factory and is now "shopping" around for technical fixes.
"That has practically never happened before as, quite rightly, Renault has always sought to preserve its technology," said Minardi.
"This news can only feed suspicions of structural problems in the engine that are not easy to solve in the short term.
"Obviously, I hope to be proved wrong as soon as the testing in Bahrain, but undoubtedly we are living through a chaotic time in formula one," he added.