I think this is BS. It's his damn choice if he wears a helmet or not. He is the one who has to live with the consequences. Same thing with seat belts. Yes, I think you should wear both but it is your choice if you do. Same with the contracts, it's his choice if he wants to do something stupid OFF of the job. Next thing you know is someone working for McDonalds will get fired for not wearing a bike helmet. Give me a fucking break...
It is called protecting your investment. If he had a huge signing bonus all that money would be lost to the team if he got injured. If someone has it in their contract to not ride or do whatever and they break the contract the team could get some cash back.