Every rider on the pro tours is part of a team. Most of them do not have a chance of winning a stage or race- but in that race they can play their part. That part may be to ferry water up from the Cars following- may be as a lead out man for the sprinters- they may have to bury themselves in the road to bring one of the top riders that has had a problem and has fallen behind. Or they may be one of the lucky ones that has a chance of winning that will have other members of the team acting as a windshield to save the good riders energy.

Or it could even be that you have a specialist skill like time trialling and you are there to get a result on the time trials. Rest of the event and you will be the domestique for those that do have a chance on the other stages.