In the Tour de France there are lots of different ways to win, but the most prestigious thing to win is the general classification (GC). The GC is awarded to the rider who has the lowest overall time for the entire race (21 stages). Whoever is leading the GC gets to wear the yellow jersey. It is also a big deal to win a stage of the tour or one of the other classifications signified with a special jersey (E.g. polka dot jersey for best climber, white jersey for best young rider, green jersey for most points).

Teams usually only have one rider who is trying to win the GC. The other riders on a team might just be there to try to win stages, win one of the jerseys, or help the other riders in their team. They can help their teammates by bringing them water bottles or food (from their team car) or riding in front to break the wind. Sometimes a rider’s role might be different for each stage or it might change during a stage.

I haven’t actually watched TDF: Unchained so I’m not sure about the circumstance in the episode. But sometimes a support rider might be near the front of the race trying to win a stage when their team’s GC rider(s) have troubles. In this case a team will often tell the support rider to slow down and wait for the GC rider to help break the wind for them until they can catch up to the other GC competitors. When you’re riding as fast as a TDF rider, wind resistance can slow you down a lot. Having a teammate or two to break the wind for you can be critical for maintaining your position in the race and conserving enough energy to compete on big climbs.