Olympic swimmer Michael Phelps could yet find himself in hot water with sponsors after a British newspaper published a photograph that appeared to show him smoking marijuana, a sports business expert said Monday.

Michael Phelps is smoking marijuana pipe. (File Photo)

Initial reaction to the article was subdued, with at least two sponsors - Speedo and Omega - saying they had no plans to part ways with the 23-year-old Olympic hero who won an unprecedented eight gold medals in Beijing in August.

The News of the World published the photo on Sunday, allegedly showing Phelps inhaling from a glass pipe which is generally used to smoke the drug.

The newspaper said the picture was taken on Nov 6, at a party at the University of South Carolina.

Phelps himself issued an apology through his agents, Octagon, admitting he "engaged in behavior which was regrettable and demonstrated bad judgment."

"For this, I am sorry. I promise my fans and the public - it will not happen again."

But David Carter, executive director of the University of Southern California Sports Business Institute, said the incident could yet come back to haunt Phelps.

The swimmer has already had to rehabilitate his image after pleading guilty to drunken driving in 2004 - a few months after he won six gold medals and two bronze at the Athens Olympics.

"He's had two meaningful indiscretions. If it seems like chronic behavior, he is doomed," Carter said.

Carter said Phelps had benefited from the timing of the affair, with US sports media and fans focused on the National Football League's Super Bowl spectacular on Sunday.

"He's lucky, the timing is actually pretty good," Carter said. "(People) care less about swimming and Michael Phelps on a weekend in which the Super Bowl is taking place."

And with interest in the Summer Olympics at a low ebb in February, Carter said sponsors could afford to take a wait-and-see approach to the matter.

"What's the hurry? The Olympics aren't on right now so there's no need to make a decision right now," he said, adding that Phelps' corporate backers could stand back and "see if he gets his act together and behaves like someone who takes his responsibilities as a spokesman seriously.

"You might have seen a more aggressive response had we been coming up on the Olympic trials," Carter added.

USA Swimming, the national governing body for the sport, and the US Olympic Committee expressed disappointment in the swimmer, but also indicated they expected him to move forward and refurbish his image as a role model for young fans and athletes.

American Gary Hall Jr., winner of four swimming medals at the 1996 Olympics, was suspended by international governing body FINA for three months in 1998 after testing positive for marijuana.

But under current World Anti-Doping Agency rules, Phelps will not face any sanction since marijuana only draws a suspension if an athlete tests positive during competition.

And Carter said many of Phelps's fans won't be put off by the incident.

"Some people don't attach consequences to that behavior," he said.

Mark Spitz, the swimming icon whose 36-year-old record of seven Olympic gold medals at a single Games was broken by Phelps in Beijing, told Usmagazine.com that he felt badly for Phelps.

"I think no one would wish this on anyone, especially the person that gave us a summer like no other in 2008," Spitz said.

(AFP via China Daily Feburary 4, 2009)