An expression when an athlete must sit on the bench and not participate in a sporting event. Various reasons include poor performance, injury, illness, or in the case of students athletes, incapable of maintaining required academic levels in school.
Greg: That's why I love being goalie. Always know my place in the pipes.
Les: (chuckles) You're riding the Pine Pony pal. Julie's one, you're two.
Greg: I'm the backup?! How could he do this to me?!