DUESSELDORF, Germany (AP) — A scene from Godfather III about sums up where the Tour de France is with doping as the 2017 edition begins on Saturday.

In the movie, Al Pacino's character Michael Corleone laments that his efforts to become a bona fide businessman are being undermined by his family's underworld connections. "Just when I thought I was out, they pull me back in," he wails.

Likewise, cycling's showcase race seemed largely to have extricated itself from the swamp of widespread blood doping that characterized Lance Armstrong's era. The 12 riders banned or provisionally suspended by cycling's governing body, the UCI, in 2015 and 2016 for using blood-boosting agents like Armstrong were largely second-tier. Just one, France's Lloyd Mondory, had previously raced in the Tour — in 2009 and 2010 when Armstrong was still competing.

But just four days before the 2017 edition gets rolling in Duesseldorf, Germany, came a reality check.

The UCI announced that Andre Cardoso, a seasoned pro who was to have raced in support of 2007 and 2009 champion Alberto Contador in his quest for another Tour title, tested positive for EPO, a hormone banned because it stimulates the production of oxygen-carrying blood cells.

EPO was also part of Armstrong's doping armory when he cheated his way to seven Tour wins from 1999-2005. Those victories were subsequently all stripped from the Texan, who has been banned for life, leaving the sport and the Tour laboring under corrosive clouds of suspicion.

Time and cycling's sustained anti-doping efforts have helped to heal some of those wounds, and to win back fans in countries like Germany, where broadcasters had turned their back on the Tour. But Cardoso's positive test shows that the race isn't out of the woods yet — and likely never will be.

"We keep saying that time is the healer of the sport and what people did 10 years ago to ruin the sport will be healed by time and the fact that nobody is doing it anymore," Team Sky rider Luke Rowe told The Associated Press.

But Cardoso's test, he added, "just puts a bad shadow on the sport again."

Describing himself as angry and frustrated, Rowe said he'd like the Portuguese veteran of seven Tours of Italy and Spain to be banned for life, "especially if you are caught with something as obvious as that."

"Guys like him should never be able to race a bike again," said Rowe, who is racing with reigning champion Chris Froome for a third time at this Tour.

Cardoso said in a statement that he has never taken banned substances, having "seen firsthand through my career the awful effects that performance-enhancing drugs have had on our sport."

But if a follow-up test also comes back positive for the Trek-Segafredo team racer, the conclusion must be that cycling still hasn't convinced all of its most experienced athletes that cheating isn't worth the risk. And that's despite the thousands of yearly tests and the regular scrutiny of riders' blood for tell-tale signs of doping.

For Brian Cookson, president of the sport's ruling body, the UCI, Cardoso's positive result shows that testing is working.

"I don't think it demonstrates that there are many, many other riders doping," he told the AP. "From time to time an athlete is foolish, and the chances are they are going to get caught."

Cycling can rightly argue that it is one of the most scrutinized sports and far from alone in being affected by the doping scourge.

Its anti-doping unit says it conducted a whopping 15,000 tests last year — the bulk of them on male professional road racers. On top of that, 41 pro teams are being monitored by the blood passport program that cycling helped to pioneer, tracking riders' blood values over time for any suspicious variations. Pro teams provide more than two-thirds of the costs.

"From being a pariah and an outcast, almost, because of our poor doping record, now I think the reverse is true," Cookson said. "We have a very good reputation in the anti-doping world and the wider sports world."

At the Tour, cycling's anti-doping unit is planning an average of eight tests each day — always including the race leader and winner of each stage, plus six others. The best riders' samples will be stored for 10 years, for possible retesting as detection methods improve. Anti-doping officials and French police have again agreed to share intelligence, to help target tests. In exceptional circumstances, sample collectors can even visit riders in the middle of the night.

The anti-doping unit director, Francesca Rossi, told the AP that Cardoso's positive test doesn't signal a renewed EPO trend.

"I'm not worrying because it's one positive for a long time. Statistically, this is acceptable," she said. "We are not anymore in the EPO era, for sure."

Tripping up Cardoso before he took the start spared the Tour further embarrassment. The 32-year-old said sample collectors visited him at home on June 18.

Irish rider Nicolas Roche, embarking on his eighth Tour, said he was surprised but also relieved that Cardoso was caught because "when someone tests positive once in a while it also means that the test works, which is in a way reassuring."

"I was just like, 'Really, do riders still think they can get away with it?'" he said.

The use of chemical boosters has been part of the story of the physically punishing Tour since its earliest days. That has never stopped millions of people from lining its roads each summer.

"You had to be naive to think it couldn't happen again. And it will happen again. It's logical. Just because we haven't seen riders caught for EPO for a while doesn't mean that riders weren't taking it," said Marc Madiot, head of the French FDJ team.

"We could meet again in five, 10, 15 or 20 years and there are still bound to people who will try to get around the rules."

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AP Sports Writers Andrew Dampf and Rob Harris contributed.