An under-50 woman in my spin class got a clot in one calf, the result of a domestic flight during which she was dehydrated. She's a racer, in very good condition. Endurance athletes like cyclists are more susceptible, not less. Good advice here:
How to prevent deep vein thrombosis (DVT) in athletes and traveling sports teams
You can start riding again when the doctor says so - generally when they take you off warfarin.