They're the only player on the team that goes out each game and gives it all they've got at the threat of burning out their arm at an early age.
You've got to give credit to the old successful workhorses who stayed strong and healthy enough to pitch into their late 30's........
One of the problems is overuse of young pitchers before their arms fully develop. It used to be you started in the bullpen, and then you became a starter when you were around 25 years-old, when the shoulders finally are fully developed and better able to handle the strain of pitching. That’s why Nolan Ryan lasted as long as he did, because he started out in the Mets’ bullpen.