It’s no surprise that cycling analysts proclaim the 2007 Tour de Franceto be a wide-open contest.No former winner will be on the start line, and only three men in thisyear’s race — Alexander Vinokourov (third in 2003), Andreas Klöden(second in ’04 and third in ’06) and Oscar Pereiro (second in ’06) — haveever reached the podium. While he may still be young enough to win cycling’sgreatest race, 35-year-old Lance Armstrong hasn’t entertained any rumorsof a comeback since retiring after taking his seventh Tour title two yearsago. And 1998 Tour winner Marco Pantani died of a cocaine overdose in 2004.

Besides those former winners, five other riders who would be capableof claiming the Tour title will be absent this year. Here’s why.Floyd Landis
After watching his Tour hopes go downhill on the slopes of La Toussuireon stage 16 of the 2006 event, Landis stunned the world the next day witha solo breakaway that was later dubbed the greatest comeback in modernTour history. Landis wore the maillot jaune into Paris as the third Americanto take the Tour. Unfortunately, the 31-year-old tested positive for exogenoustestosterone after stage 17, and has spent the past year trying to proveto the world, as well as the United States Anti-Doping Agency, that hedidn’t cheat. While Landis remains in legal limbo, the American is prohibitedfrom competing in professional races.Jan Ullrich
After he became the first German to win the Tour at the age of 23 in1997, Ullrich was supposed to be the next multiple-Tour winner. Althoughhe sat in Armstrong’s shadow for the following seven years, Ullrich finallylooked poised to take a second Tour victory in 2006 — only to be barredfrom the race when he was implicated in a Spanish doping investigation,dubbed Operación Puerto. Ullrich has vehemently denied workingwith Eufemiano Fuentes, the so-called doping doctor at the center of thePuerto blood-doping ring. But a DNA test conducted this past April by Germanauthorities matched Ullrich’s DNA with blood seized in the Puerto raidon Fuentes’s office. Perhaps in anticipation of the bad news, Ullrich officiallyretired two months earlier.Ivan Basso
Basso twice finished on the podium behind Armstrong, third in 2004and second in 2005. After crushing the field to win the 2006 Giro d’Italia,the Italian looked poised to challenge Ullrich at the Tour. But Basso wasalso linked to the Puerto scandal and, like Ullrich, was removed from histeam’s roster before the start. After breaking with the Danish CSC team,Basso signed a controversial contract with Discovery Channel in 2007 toride as Armstrong’s replacement. But Basso couldn’t elude his past withPuerto, and after cycling’s governing body, the UCI, obtained documentsfrom the Spanish authorities,
Basso resigned from the American team. Then, just days after vehementlydenying any association with Dr. Fuentes, the Italian star changed histune. He admitted to only having attempted to dope, but his national Olympiccommittee recommended he be suspended for 21 months.Francisco Mancebo
The Spaniard finished fourth overall in the 2005 Tour, but he too waslinked to Operación Puerto and had to sit out the 2006 Tour.Currently Mancebo rides with the Spanish pro continental team, Relax-GAM,which did not receive an invitation to the Tour. Also on that team is OscarSevilla, another former Tour rider implicated in the Puerto investigation.Tyler Hamilton
Hamilton looked poised to become the next American in yellow afterhe finished fourth at the 2003 Tour de France. But the New Englander testedpositive for homologous blood doping at the 2004 Vuelta a España,and fought a losing battle to clear his name. Hamilton served a two-yearsuspension and returned to racing in 2007 with the Russian pro continentalteam, Tinkoff Credit Systems. But Tinkoff is not a UCI ProTour squad, anddid not receive a wild-card invite to the Tour. Not that it mattered —in May the team suspended him before the Giro because of his alleged Puertoconnection.