Major League Baseball teams are traveling in and out of states, so there must be a way around travel restrictions.
There is an exemption for professional teams, but it states it does not apply to amateur or collegiate activities. Of course this could change.
Players, coaches, and any team or league staff coming to New York from a designated state must always quarantine in single rooms at their accommodations/lodging while in New York, except for activities related to team practice, meetings, and competition. Teams and leagues must limit the number of staff traveling to New York to only essential personnel required to allow the team to compete while maintaining all applicable health and safety standards. This document applies to any professional athletic activity such as: baseball, basketball, professional vehicle racing (e.g, NASCAR), tennis, etc. This does not apply to amateur or collegiate activities.