Being quiet does not win you any favors in softball, especially at tryouts and on road trips. Being part of the team is a big deal, on and off the field. Coaches want happiness and bonding off the field, and girls who are seen as "loners" are generally not well accepted, at least from my experience.
Being quiet doesn't mean you're a loner or that you're unhappy. Not that you said that, but it seems you're lumping all that together. If you don't like your teammates and don't like being around them, then sure, that's problem whether you're quiet or loud. But as long as you get along with everybody and can hang out with your teammates and have basic social skills, I think you can be pretty quiet and be fine.