It's tough to say who Lance Armstrong's toughest foe will be this morning as the 97th Tour de France begins in Rotterdam, Netherlands.
The seven-time Tour champion certainly has his work cut out for him on the roads of Holland, Belgium and France over the next three weeks in what he says will be his final time to compete in the world's top bicycle race.
There's little doubt that Armstrong would love to reclaim the top spot on the podium from reigning champion and former teammate Alberto Contador.
Armstrong and Contador parted ways after one contentious season on the Astana team with Lance convincing RadioShack to sign on as a sponsor for his hand-picked dream team led Armstrong's longtime team director Johan Bruyneel and featuring an all-star group of supporting riders, including top American riders Levi Leipheimer and Chris Horner.
Apart from Contador, the 38-year-old Armstrong is likely to face tough challenges from much younger riders such as Frank and Andy Schleck, Ivan Basso, Cadel Evans and others. If Armstrong is going to wear the yellow jersey into Paris, he'll need to be in top form and have more than a little bit of luck on the roads of France.
But perhaps the more threatening opponent facing Armstrong is a disgraced former teammate who can't find a top-level team that will take him and hasn't ridden in the Tour de France in four years.
Allegations of systematic, long-term doping made last month by former American star Floyd Landis have hounded Armstrong throughout the spring and early summer, drawing unwanted attention from the media as well as former BALCO investigator Jeff Novitzky.
To be sure, Landis - winner of the 2006 Tour de Georgia, including a victory that year in the Stage 3 time trial that finished in downtown Chattanooga - doesn't have the best record of honesty on the subject of illegal performance enhancement. After having the 2006 Tour de France title taken away for a positive doping test, Landis told anyone who would listen that he had been framed by Tour officials and the French laboratory that conducted the tests.
Only when the media spotlight had begun to fade without his vindication did Landis suddenly have a change of heart on the eve of this year's Tour of California and decided to admit his guilt - while at the same time implicating (so far without proof) several former friends and teammates, including Armstrong, Leipheimer and current BMC Racing Team rider George Hincapie.
To say the least, Landis has a major credibility problem on the subject of doping after years of denials and publishing the ironically titled book "Positively False" denying everything he now admits he was doing all along.
But as with most things in life, where there's smoke you often find fire - and there's a lot of smoke when it comes to pro cycling's long and difficult history with doping.
Doping has cut a deep scar across the sport of professional cycling dating back to the Festina scandal, which knocked an entire team out of the 1998 Tour mid-race. Over the past decade - and particularly in more recent years - the sport's top officials have been quick to punish cheats when they can find them in an attempt to get the problem under control.
This week, Swiss cyclist Thomas Frei was given a two-year ban for a positive test for the banned blood-booster EPO. and three other riders were banned from the Tour of Austria for alleged doping.
Landis isn't the first to accuse Armstrong of cheating, and he likely won't be the last. But so far Armstrong has passed every drug test he's taken (and he's taken plenty), and no conclusive proof has been found to disprove his assertion that he's clean. Those who would believe Armstrong is a liar would love nothing more than to see him end his career in disgrace.
So with the international and French media searching for any chink in Armstrong's armor and investigators looking for evidence to claim the most high-profile scalp possible in the name of anti-doping, the famous Texan will find little rest on or off the bike from now to July 25 when the race ends in Paris on the Champs-Élysées.
And while there is no doubt the ever-competitive Armstrong would love to wrap up what has been a spectacular career with his eighth Tour de France title, perhaps he should be satisfied if he can successfully negotiate the cobblestones of Belgium and the long climbs up the Alps and Pyrenees without losing his reputation as the best cyclist of the past decade.
E-mail Jim Tanner at jtanner@timesfreepress.com