i think that you should talk with your husband about it. perhaps, if you talk about it, you will be able to come to a conclusion. then talk to your son, both you and your husband, together. figure out his feelings. let him know he is NOT in trouble, and he is NOT going to be yelled at - he needs to share his feelings.
i dont think he should have to play a sport he doesnt want to play. if it were the middle of the season, yes, he should finish the season, but he shouldnt have to play again this year if he doesnt want to.... but you and your husband need to have a talk about it and figure out what your son is feeling.
sometimes when something is forced on a kid, they are naturally going to rebell from that. maybe remind your husband of this - that pushing his son to play baseball isnt going to make him want to play, but supporting the things he wants to do will make him more confident. if your husband is a strong baseball fan, does that make him a loud baseball parent? is he yelling things during the game, positive or negative? this could make your son uncomfortable and embarrassed.
good luck with this. the most important think is to talk to your husband FIRST and figure out what you should do. dont give your son the impression that you arent a team... make sure you try to present yourselves as a unit. then make sure to consider your son's feelings.
sports are extra things in life that kids are lucky to do. they arent a requirement for anything. there are things that he could do that is much more important than sports, such as music or ... etc educational field trips, something else. sports arent something that are very important. sure, exersize is very important, but there are other, fun, less structured ways for that to happen as well.
perhaps, like you said, if dad would play baseball WITH him, he might start having fun with it and want to play it in the future, as long as there isnt any pressure to MAKE him play. i HATED playing softball or kickball when i was in school. i didnt like to be watched that closely, i didnt like being the center of attention, and i was always SO EMBARRASSED if i was hitting or kicking or catching.... i didnt like attracting that kind of attention. however, i LOVED playing soccer because even though the ball is usually with one person, you are a team! there isnt that pressure that everyone is looking right at you all the time. there is teamwork. its different with soccer.
i never played either of theses sports on a "team" but only in gym class. i did play volleyball for 2 years in high school and i liked that too because it was a TEAM thing. there wasnt much focus on just one person when you have to work together.
either way, talk it out. figure out how to come to a solution together. before presenting a solution, ask your son what he feels, what his solutions are. :D
good luck