I was a child who was told repeatedly that I should not be riding ponies, it would be no good for my violin-playing. One day, when I was about 12, I went for my violin lesson to be told by my teacher that I had to choose between horse-riding and violin lessons. She would not teach me any more if I would not commit to stopping riding. She was very blunt about it. I handed her back the violin there and then, and have never picked one up since. My teacher was gobsmacked, she could not conceive of a child who could possibly prefer ponies to violins and had issued an ultimatum with the firm belief that I would choose the violin. She made several attempts to persuade me back to violin lessons by saying we could come to an agreement, but my faith in her had been utterly shaken and I did not believe she meant it, and that she would be back to telling me to stop riding again before long.
I do regret now not seeking another teacher, but I was 12, and a fairly 'young' 12 at that. I had played in the local junior youth orchestra, and the pressure was placed on me because at 13 I would have been eligible to apply to join the City Youth Orchestra. I enjoyed playing in an orchestra. My husband is an entirely self-taught musician, has never had a lesson in his life. He plays in a moderately successful band with his mates, and I'm a bit sad as an adult that I don't have that ability any more, because when I was a child an adult made me take a certain path.
If I were the OP, I would not be making my child do or not do anything. I would be enabling them to make the choices they want to make. If they love their music and really hate team sports, help them give up the team sport. But to make a child give up one thing in order to safeguard something an adult places a lot of value on may not win the child over in the long run.
I would love to go back to that teacher and tell her what a mistake she was making, forcing me to choose. I still ride and have horses now, having competed at a high level before I had children. I'd love to be able to pick up a violin on an evening, and join in the music sessions my husband's band have in our garden, but the combination of a stubborn child and a stubborn teacher means I have lost out, and would have lost out whichever way I had chosen.