Santa Rosa's Levi Leipheimer said Sunday he's retired from professional cycling, becoming the latest casualty of a massive doping scandal that saw disgraced champion Lance Armstrong banned from the sport for life.

Leipheimer, 39, was a former teammate of Armstrong who, along with 10 other cyclists, cooperated with U.S. Anti-Doping Agency investigators in their examination of drug use during Armstrong's reign in the sport.

The five riders who were active at the time received six-month suspensions and had some past results nullified. In the wake of the tumult, George Hincapie retired and Leipheimer was fired by his former team Omega-Pharma-Quick Step. Christian Vande Velde, Dave Zabriski and Tom Danielson are still riding professionally. All are Americans.

Leipheimer's suspension ended March 1. Despite expressing interest as recently as December in continuing his professional cycling career, no team signed him.

"I'm retired," he told The Press Democrat Sunday after addressing the crowd gathered in downtown Santa Rosa for the final stage of the Amgen Tour of California. "It's just been an unceremoniously retired."

The news was met with some resignation among cycling fans Sunday. Enthusiasts praised Leipheimer for raising the profile of cycling locally, and expressed disappointment that his career was ending ignominiously.

"I kind of figured that was going to happen," said Fred Woods of Castro Valley. "It's kind of sad. I think he's had a good career and he shouldn't have been fired from his team."

Longtime tour announcer Dave Towle invited Leipheimer to the stage Sunday morning, calling Leipheimer "The King of the Amgen Tour of California," which he won three times.

"A huge, huge thank you for all you have done," Towle said, calling Santa Rosa "Bike City U.S.A."

Leipheimer, who has enjoyed superstar status among Sonoma County's cycling community, was routinely celebrated on the stage when the Amgen Tour of California rolled into town in years past.

In 2008, when Leipheimer was prohibited from riding in the Tour de France because his Astana team was being penalized for prior doping violations, "Let Levi Ride" stickers and buttons popped up on shirts and cars in Sonoma County.

In 2010, American cyclist Floyd Landis, who had been suspended and had his Tour de France victory stripped because of drug use, leveled allegations of doping against Leipheimer. Leipheimer called the allegations "jealousy," "bitterness" and a "vendetta."

It was largely Landis's accusations that sparked the investigation that eventually brought down Armstrong and led to admissions by the other riders connected to the seven-time winner of the Tour de France.

Leipheimer testified before a federal grand jury and eventually admitted to U.S. anti-doping authorities to long-time, systematic use of blood doping and performance enhancing drugs. He was stripped of his race results from June 1999 to July 2006 and in July 2007. The latter period included his third-place finish in the Tour de France.

Still, the low-key retirement disclosure caught some fans off guard Sunday.

"I'm surprised," said cycling enthusiast Kristin Sheerin of Santa Rosa. "I have mixed feelings about him. He's obviously a hometown hero for us cyclists in Santa Rosa. And I admire his honesty in coming clean."

"I hope he continues to be a driving force in the cycling community in Sonoma County," she said. "I was glad to see him here, I wish him well and I'll continue to ride the GranFondo," Leipheimer's signature charity event.

Chris Mulligan of Windsor said all riders in the investigation should have received the same punishment. "If you did it to one, you should have done it to both," he said of Armstrong's lifetime ban versus the six months given to Leipheimer.

Still, Mulligan remains somewhat attached to Leipheimer's legacy.

"I have a shirt that is signed by him," he said. "I've ridden the GranFondo twice for what he's done for cycling. I'll appreciate him for that."

From behind the stage on Sunday morning, Leipheimer said he is "transitioning into the rest of my life."

"I sort of miss racing," he said. "I still love riding my bike."

He rides regularly and competitively, but said his focus now is promoting the GranFondo, a mass ride in the fall that attracts 7,500 cyclists.

He said no one has asked him to step down from his position with the GranFondo because of the doping admission. He called any comparison of his situation to Armstrong's being forced out of his charity, Livestrong, "apples to oranges."

Armstrong stepped down from his leadership position with the cancer awareness charity he formed after battling the disease, when it was feared the taint of years of cheating and lying would negatively impact the charity's work.

Leipheimer said he will remain the face of Levi's GranFondo, a huge event that has raised about $900,000 for local non-profit groups since it was first staged in 2009.

"Everyone has been so supportive," he said. "I've just been overwhelmed by everyone's understanding."

The success of the GranFondo doesn't require him to be a professional cyclist, he said. "It's not about professional cycling, it's about sharing the love of the bike."

"That's what it's always been about," he said.