How would you say Varsity in Spanish, as in a Varsity sport'
Googling around suggests equipo titular for another possibility. If you are translating this for a school, you may want to include the English as well to make your designation clear.
I hate to tell you, but this word doesn't really translate into Spanish. You will have to use a work-around. The varsity team means the main team at a school or university, and you might be able to say "el equipo principal universitario (escolar). Although the word varsity is a shortening of the word university, it is also used in the US for high school and even middle school sports, and refers to the team made up of the best (usually oldest) athletes.
Give us a full sentence and we might be able to suggest translations.