Manny Pacquiao’s star is starting to lose its luster, a Hall of Famer said over the weekend.

Barry McGuigan, the Irish featherweight who writes a column for the British daily tabloid The Mirror, expressed the opinion that Pacquiao was a far cry from the punching demon who terrorized the likes of Erik Morales and Marco Antonio Barrera with his razor-thin 12-round split decision victory over Juan Manuel Marquez two weeks ago in Las Vegas.

“You might think that Pacquiao would be too much for (unbeaten British prospect Amir) Khan — who is out again against Martin Kristjansen next week — at this stage in his career. I’m not sure after watching the Pacman edge a split decision against Juan Manuel Marquez a fortnight ago. It looks to me as though there is not too much left in the tank,” said McGuigan, who reigned as World Boxing Association 126-lb ruler in the mid1980s.

McGuigan, now 48, even floated the idea that should Pacquiao beat David Diaz on June 28, he might take on Khan in September.

The 5-10 Khan, 21, parades a 16-0 win-loss card with 12 knockouts, and was the silver medalist in the 2004 Athens Olympics.

“Sound ridiculous? It is a long shot for sure, but suddenly, not out of the question. Pacquiao moves into Khan range in June when he challenges David Diaz for the WBC lightweight title,” said McGuigan, who had wrested the WBA crown by besting the durable Panamanian Eusebio Pedroza.

Khan is currently rated No. 5 by the WBC in the 135-lb category and No. 7 by The Ring magazine.

McGuigan observed that the plan to pit Pacquiao against Diaz is a clever move since “Diaz is certainly the weaker of the lightweight champions.”

McGuigan continued: “He (Pacquiao) seems to be having trouble with dedication and commitment. He is a fantastic fighter, a superstar of the game, but there comes a time in a boxer’s career when you get fed up of being hit in the head. When that happens, it is the day you start to die as a fighter. Only the fighter knows when that moment arrives, when that one punch too many has landed.”

After Pacquiao came out victorious against Marquez, McGuigan, who was inducted into the Hall of Fame in 2005, began entertaining thoughts about the descent of the 29-year-old Filipino.

“Remembering when that day came for me and looking at Pacquiao against Marquez there were a couple of moments when I thought: Hello, has Manny crossed that line?” asked McGuigan, who went to the extent of saying that he won’t be shocked if Diaz upsets Pacquiao.

“He might not get past Diaz even. Everyone will pick him but it would not surprise me to see Diaz stop Pacquiao at lightweight,” added McGuigan, who compiled a career record at the professional level of 323 with 28 knockouts.