In its 2005 list of the 100 most powerful celebrities, Forbes Magazine ranked Michael Vick No. 33, just behind Denzel Washington and Rod Stewart, just ahead of Bette Midler and the Olsen twins.

The Atlanta Falcons quarterback had recently signed a 10-year, $130 million contract that included a $30 million bonus and had endorsement deals with Nike, Kraft, Coca-Cola, Rawlings and other companies. Vick's potential as a marketer seemed as limitless as his potential on the field.

Two years later, Vick's appeal is plunging, and not just because of the investigation into his possible involvement in dog fighting at a home he owned in Surry County. Even before the dogfighting case surfaced, Vick's negatives were rising and his positive ratings falling, according to the experts who track the demographic appeal of celebrities.

"There's obviously some kind of undercurrent against his image among sports fans, even before that story broke," said Henry Schafer, president of Marketing Evaluations Inc., which compiles "Q Scores" of celebrities. Potential advertisers use these numbers to help guide decisions on who they'll link their products with.

The backlash is growing. Allegations of animal cruelty have raised an outcry that other types of celebrity misbehavior — assault, gun charges, even drug use and drunk driving — often do not.

"We're getting kind of immune to that sort of stuff because we see it so much," said Bob Dorfman, executive vice president of Pickett Advertising, in San Francisco. "This stands out in its uniqueness, because it's about animals, and everybody in this country loves dogs."

Vick has already canceled scheduled appearances at summer football camps at Christopher Newport University and William and Mary. Air Tran Airways dropped Vick as a spokesman.

Last week, the Humane Society of the United States called on Nike, Vick's biggest sponsor, to sever its ties with him. The company said it plans to stick by him.

"He is rightfully presumed innocent and afforded the same due process as any citizen, rather than be tried in the court of public opinion," a company spokesman said.

Yet, for a corporate pitchman, the court of public opinion can carry more weight than even a criminal court. No matter the outcome of the dog fighting investigation, Vick and his handlers face a huge challenge in repairing his battered image.

"The longer this thing stretches out, the worse it is," said Joel Rubin, CEO of Rubin Communications Group in Virginia Beach.

In the short-term, there are things Vick can do to manage the crisis, said Eric Dezenhall, an expert who has written books on public relations damage control. His firm, Dezenhall Resources, helps clients through "crisis, conflict and controversy."

In an e-mailed response to questions, Dezenhall said that although people assume controversial figures can vindicate themselves by telling all, the reality is that celebrities like Vick are limited in what they can say because public statements are admissible in court.

If Vick does comment publicly, Dezenhall suggests, his statements should be personal in nature, not focused on the case. He should acknowledge that it's been a rough time and thank fans for their support. He would advise Vick not to try any public relations stunts, noting that those are inevitably seen for what they are.

As for the likelihood of Vick losing more endorsement deals, it depends on the company, Dezenhall said. Those known for having "street cred" will often stay with their celebrities through a scandal. More conservative companies won't. McDonald's, for example, dropped Kobe Bryant after a sexual assault charge in 2003. Nike didn't.

In the end, all Vick can hope for is to make a bad situation less bad, Dezenhall said. Hoping you can make a bad situation good is not realistic.

"Remember that the objective is damage control, not damage disappearance," Dezenhall said. "The damage is already done."

In fact, damage to Vick's popularity had begun to mount even before investigators raided Vick's home in April. Two years ago, he was rated as the third-most appealing NFL player, behind Peyton Manning and Brett Favre.

Now Vick is ninth. His rating among all 480 sports personalities evaluated has dropped from 34th in 2005 to No. 125 in 2007. The 2007 scores were tabulated before the dog-fighting story broke.

"Michael, from an endorsement standpoint, was a guy who was coming back to the pack a little bit," said Steve Rosner, co-founder of the New Jersey sports marketing firm 16w Marketing LLC.

Rosner cited two reasons: negative publicity off the field and disappointing performances on it.

Off the field, Vick's been involved in a series of incidents. Last November, he was fined $10,000 for making an obscene gesture to Atlanta fans. In January, he initially refused to surrender a water bottle to airport security in Miami. The bottle was found to have a hidden compartment that police said contained a "dark particulate" with an aroma "closely associated" with marijuana. Vick was not charged.

Earlier in 2006, the former Virginia Tech star also settled a civil suit filed by a woman who said he infected her with genital herpes.

Then there was the controversy surrounding his younger brother Marcus, who was kicked off the Tech football team after a series of legal and on-field problems.

On the field, Michael Vick has failed to fully develop as a quarterback, remaining a dangerous runner but a scattershot passer. His completion percentage has fallen the last two years and his passer rating was 20th in the league last season. The Falcons have missed the playoffs the past two years.

"He has to show that his team can win," Rosner said. "He's shown he's a great athlete, absolutely. He's shown at times he has the physical tools. To get that next level, it's all about winning."

Given his other troubles, the experts say winning alone won't be enough to restore Vick's image. For an athlete fallen from grace, the road back can be long. It's been three years since a rape case against Bryant was dismissed, and the NBA star is "on a very slow return" Schafer said.