Muhammad Ali has been placed on life support — and his family fears that it “likely won’t be long until he passes away,” according to a report.

The 74-year-old boxing legend was hospitalized in Scottsdale, Ariz., for a respiratory issue on Thursday and insiders tell Radar Online that his loved ones are now rushing to his side because it appears his condition has worsened.

“He needs every bit of fight he’s got left to survive,” a source told the website. “Doctors are telling the family that it likely won’t be long until he passes away.”

Another source said Ali’s vitals “are terrible” at the moment and he is currently relying on medical help to breathe.

His rep told the Associated Press on Thursday that the respiratory problems that the former heavyweight champion was facing had been complicated by the Parkinson’s disease he was diagnosed with in the 1980s.

Ali is known almost just as much for his way with words as for his boxing skills:

The spokesman said Ali was being treated at an unidentified hospital and was in “fair condition” and that a brief hospital stay was expected.

But it appears that things got more serious overnight.

“His children are all extremely concerned and dropped everything to be with him,” a source told the Daily Mirror. “They fear the worst.”

Ali has been hospitalized numerous times in the past, most recently in early 2015 when he was treated for a severe urinary tract infection that was initially thought to be pneumonia.

He has looked increasingly frail in public appearances, including April 9, when he wore sunglasses and was hunched over at the annual Celebrity Fight Night dinner in Phoenix, which raises funds for treatment of Parkinson’s.

His last formal public appearance before that was in October, when he appeared at the Sports Illustrated Tribute to Muhammad Ali at The Muhammad Ali Center in his hometown of Louisville, Kentucky, along with former opponents George Foreman and Larry Holmes.

Ali has suffered from Parkinson’s for three decades, most famously trembling badly while lighting the Olympic torch in 1996 in Atlanta. Despite the disease, he kept up a busy appearance schedule until recently, though he has not spoken in public for years.

Doctors say the Parkinson’s likely was caused by the thousands of punches Ali took during a career in which he traveled the world for big fights.

An iconic figure who at one point was perhaps the most recognized person in the world, Ali has lived quietly in the Phoenix area with his fourth wife, Lonnie, whom he married in 1986.

News of his hospitalization brought well wishes from boxers and others on Twitter.

With Post wires