Alexandre Vinokourov and Joseba Beloki are definite non-starters for the Tour de France, as Jan UllrFew things are certain in professional cycling, although in recent years there have been exceptions; each June, as the Tour de France start nears, we can be sure of the following: Jan Ullrich's fitness will be under the microscope, the press will become obsessed with doping scandals - fuelled by one book or another - and there will be some high-profile absentees from Le Grande Boucle. While most reports in the past week have centred on the controversial publication of David Walsh's book 'LA Confidential,' clearly a growing legal headache for defending champion Lance Armstrong, those with racing on their mind will have been equally struck by the loss of Joseba Beloki and Alexandre Vinokourov from this year's Tour field. If Walsh's book is setting out to explode Armstrong's image, then the Texan will at least take comfort from the fact that two riders who would have been keen to similarly blow apart his bid for a record sixth Tour will be watching at home on TV. If it's certain that the opening press salvoes in Liege will centre on Walsh's tome, then it's equally certain that on the road at least, Armstrong's Tour task was hugely simplified this week. Oddly, in many ways - despite the legal battles - it has been a good week for the Texan. Ullrich, still a little lacking on the steepest gradients, lost the lead of the Tour of Switzerland, as well as the services of 'Vino,' the team mate who was sure to give him some much-needed tactical options. Meanwhile Beloki's absence will reduce the aggressive nature of much of the racing. It was Beloki who revealed the first chinks in Armstrong's armour last July, on the hairpins to Alpe d'Huez, even if Iban Mayo ultimately claimed the stage win. So how many rivals will the American really have to watch? Right now, it boils down to Ullrich, Tyler Hamilton, and Mayo. Those seem to be, at the moment, the three riders capable of ending the Armstrong Era. Off the road, it's a different matter, as teams of high-profile lawyers in London, Texas and Paris, prepare to lock horns... for some time to come, no doubt. Walsh's book may be on sale in France but Armstrong utterly denies the use of any performance enhancing products.