Coloccini has been linked with Atlético Madrid, Zaragoza and Seville, and an injection of capital would reduce Newcastle’s overdraft at a critical time.
The policy is being recommended by Seymour Pierce, the investment bank handling the sale.
Alan Shearer, who hopes to be appointed Newcastle’s permanent manager, was not intending to rebuild his team around any of the three players.
Newcastle winger Jonas Gutierrez insists he has not been contacted about a possible loan move to Porto.
The Argentina international admits he is not happy about playing in England's second tier, but he insists he does not know anything about a switch to Portugal.
He told media in South America: "I only know about the rumours, nobody has contacted me with this option.
"To play in the second division in England is not a dream, but it depends on Newcastle."