The Magpies manager says the Argentine centre-back has suffered "a reaction" in training and will remain absent.
Newcastle United manager Rafael Benitez has told reporters, as quoted by the Shields Gazette, that captain and centre-back Fabricio Coloccini will still not be fit to make a return to the side after suffering a setback in training this week.
The Argentine defender has not played a single minute of football for the club in two months since suffering a calf injury on the squad's training break to La Manga in February.
It had been hoped that the 34-year-old would finally be fit to return in the crucial home clash with Swansea City this weekend after returning to full training this week.
However, Benitez has revealed to reporters that those hopes have been dashed, claiming that the much-maligned Magpies man has suffered a "reaction" and will be ruled out of the club's fight yet again on Saturday.
The Spanish manager said, as quoted by the Shields Gazette: "He had a reaction the other day when he was training. We will see how he progresses."
The news is likely to incense Newcastle fans even further, with some supporters having accused their captain of shying away from chances to subject himself to scrutiny by taking his place in the side's back line.
It has even been suggested that Coloccini has been exaggerating the extent of his injury problems so that he does not have to be thrown into the bear pit that is the club's desperate struggle to stay afloat.
Meanwhile, his extended absence is just one of a number of injury problems Benitez is having to cope with in defence, with Steven Taylor also set to miss out and Daryl Janmaat ruled out through a combination of a groin complaint suffered against Southampton and the two broken fingers he sustained punching the dressing room wall last weekend.
That is likely to leave the manager having to throw together a makeshift back line for the must-win clash with the Swans, which is likely to see Chancel Mbemba and Jamaal Lascelles partnered in central defence.
However, Benitez did confirm that popular full-back Paul Dummett will be ready to return, stating: "Dummett is coming back. Taylor, Janmaat and Coloccini are not available. We have to manage with the players we have."
There is another boost as Jack Colback returns from a two-game suspension, and the versatile player could well find himself playing at full-back given the defensive concerns.
Newcastle are six points adrift of safety going into the weekend's fixtures and could have fallen further behind by the time they kick off, with 17th-place Norwich City hosting 18th-place Sunderland in the early kick-off.