Standwarmer
When in a sport you never play and heat up the area where the starters stand, when they need a rest, and your coach doesn't let you sit down on the bench, even thought you never play. (benchwarmers)
Person 1: Hey I heard that you are a bench warmer for your new team.
Person 2: Actually I am a Standwarmer, my coach never lets me sit down!
Person 2: Actually I am a Standwarmer, my coach never lets me sit down!