Count your blessings. As mentioned before, at least he has a spot on the field. We have a potential draft prospect locked down in CF. A top player is transferring in. My son would be a starter on any other team in the state, but he may not get playing time on his HS team until his senior year due to the high skill level of the other players and politics. So we just tell him to keep working hard and continue to get better. We tell him he needs to be so good it would make the coach look like an idiot to bench him. He gets playing time with his club team and he performs well for them (they face tougher competition than HS). As far as I'm concerned...he's learning patience, how to fight for playing time, and that life isn't always fair from his HS team.
I was told by a P5 coach just recently there is an appropriate time to talk with a coach about playing time/position. He recommended our son reach out to his coach now, before the season, to discuss his goals and aspirations for the upcoming season.