How do I win over "one player coaches"?

My coaches constantly want our big man with the ball because he's the "best" player. I don't want to get subbed out so I obviously give it to him but i knpw I can do more given the opportunity. I have a game tomorrow and I'm worried... Coaches are probably going to make me do the same thing.. Yet they always yell at me for not helping him enough... Any advice??